Roaming Connection Problem, Quectel EC 25E, Telekom Sim

That's correct. Modem will receive this information along with the IP address over signalling from the carrier, then OpenWrt will issue a QMI request to the modem (using uqmi) to obtain this information.
Using AT command we can verify what is on the modem.

I dont seem to be able to connect OpenWRT as a client to my mobile hotspot.

Network Scan works and sees my hotspot P20Pro.
Tried with 2.4GHz and 5GHz, cant use a password on the hotspot because OpenWRT needs wpa-supplicant for that, so I went with open (no password).

This is what the wireless menu and the status page looks like after a few seconds, but it never shows up in my mobile phone in the list of connected clients.



root@OpenWrt:~# ifstatus mobilehotspot
{
        "up": false,
        "pending": false,
        "available": true,
        "autostart": true,
        "dynamic": false,
        "proto": "dhcp",
        "device": "wlan0",
        "data": {

        }
}

I dont know what I am doing wrong...

EDIT:
I was using this guide: https://openwrt.org/docs/guide-user/network/wifi/connect_client_wifi

You can build the image will all the necessary packages included.
https://firmware-selector.openwrt.org/

Thanks for that!
I was able to get a list of all software packages on my installation and was able to get an image with everything in it to support my hardware.

I wanne really thank you for all the ideas and time you have come up with to try and solve this, it really means a lot to me and is very helpful, I hope we can find the solution at the end.

I did a completly fresh install with that image, so now I have a new OpenWrt: OpenWrt 22.03.5 r20134-5f15225c1e / LuCI openwrt-22.03 branch git-23.119.80898-65ef406

With this I was able to connect to my mobile hotspot and I was online at that time, so that worked now.

root@OpenWrt:~# ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 56 data bytes
64 bytes from 8.8.8.8: seq=0 ttl=111 time=101.004 ms
64 bytes from 8.8.8.8: seq=1 ttl=111 time=93.030 ms
64 bytes from 8.8.8.8: seq=2 ttl=111 time=91.775 ms
64 bytes from 8.8.8.8: seq=3 ttl=111 time=65.462 ms
^C
--- 8.8.8.8 ping statistics ---
4 packets transmitted, 4 packets received, 0% packet loss
round-trip min/avg/max = 65.462/87.817/101.004 ms
root@OpenWrt:~# nslookup openwrt.org 8.8.8.8
Server:         8.8.8.8
Address:        8.8.8.8:53

Non-authoritative answer:
Name:   openwrt.org
Address: 139.59.209.225

Non-authoritative answer:
Name:   openwrt.org
Address: 2a03:b0c0:3:d0::1af1:1

Even my LAN connected laptop was online with that setup. Just as you would expect!

Then I added the LTE interface back in and also disabled the wifi client connection, but I can enable that again any time I would need OpenWRT to be online for software installs.

After the LTE interface activated I also got the LTE_4 interface to show up again with its 10.x.x.x IP.
At this point I had no internet connection via the LTE interface.

root@OpenWrt:~# ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 56 data bytes
^C
--- 8.8.8.8 ping statistics ---
5 packets transmitted, 0 packets received, 100% packet loss
root@OpenWrt:~# nslookup openwrt.org 8.8.8.8
;; connection timed out; no servers could be reached

I changed the config file part of the LTE interface again as before.

config interface 'LTE'
        option proto 'qmi'
        option device '/dev/cdc-wdm0'
        option pdptype 'ipv4'
        option plmn '293041'
        option autoconnect '1'
        option modes 'lte'
        option apn 'internet.telekom'
        option auth 'none'
        option dhcp '0'

and then after a restart of the LTE interface via GUI I am getting Error: Unknown error (NETWORK_REGISTRATION_FAILED) in the GUI.

root@OpenWrt:~# ifstatus LTE
{
        "up": false,
        "pending": false,
        "available": true,
        "autostart": false,
        "dynamic": false,
        "proto": "qmi",
        "data": {

        },
        "errors": [
                {
                        "subsystem": "qmi",
                        "code": "NETWORK_REGISTRATION_FAILED"
                }
        ]
}
root@OpenWrt:~# ip r
192.168.111.0/24 dev br-lan scope link  src 192.168.111.1 
root@OpenWrt:~# ip l
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel master br-lan state UP qlen 1000
    link/ether 4a:5f:40:e8:74:a8 brd ff:ff:ff:ff:ff:ff
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP qlen 1000
    link/ether f6:f0:fc:4c:50:c8 brd ff:ff:ff:ff:ff:ff
5: wwan0: <POINTOPOINT,MULTICAST,NOARP> mtu 1500 qdisc fq_codel state DOWN qlen 1000
    link/[65534] 
6: br-lan: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP qlen 1000
    link/ether 4a:5f:40:e8:74:a8 brd ff:ff:ff:ff:ff:ff

This is the system log from the reconnect:

Fri Jul 28 23:51:10 2023 daemon.notice netifd: Interface 'LTE' is now down
Fri Jul 28 23:51:47 2023 daemon.notice netifd: Interface 'LTE' is setting up now
Fri Jul 28 23:51:47 2023 daemon.notice netifd: LTE (16758): Waiting for SIM initialization
Fri Jul 28 23:51:47 2023 daemon.notice netifd: LTE (16758): Failed to parse message data
Fri Jul 28 23:51:48 2023 daemon.notice netifd: LTE (16758): PIN verification is disabled
Fri Jul 28 23:51:48 2023 daemon.notice netifd: LTE (16758): Setting PLMN to 293041
Fri Jul 28 23:51:48 2023 daemon.notice netifd: LTE (16758): Device does not support 802.3 mode. Informing driver of raw-ip only for wwan0 ..
Fri Jul 28 23:51:48 2023 daemon.notice netifd: LTE (16758): Waiting for network registration
Fri Jul 28 23:51:49 2023 daemon.notice netifd: LTE (16758): Starting network LTE
Fri Jul 28 23:51:50 2023 daemon.notice netifd: LTE (16758): Unable to connect IPv4
Fri Jul 28 23:51:50 2023 daemon.notice netifd: LTE (16809): Stopping network LTE
Fri Jul 28 23:51:50 2023 daemon.notice netifd: LTE (16809): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "LTE" } (Permission denied)
Fri Jul 28 23:51:50 2023 daemon.notice netifd: Interface 'LTE' is now down
Fri Jul 28 23:51:50 2023 daemon.notice netifd: Interface 'LTE' is setting up now
Fri Jul 28 23:51:50 2023 daemon.notice netifd: LTE (16817): Waiting for SIM initialization
Fri Jul 28 23:51:50 2023 daemon.notice netifd: LTE (16817): Failed to parse message data
Fri Jul 28 23:51:50 2023 daemon.notice netifd: LTE (16817): PIN verification is disabled
Fri Jul 28 23:51:50 2023 daemon.notice netifd: LTE (16817): Setting PLMN to 293041
Fri Jul 28 23:51:51 2023 daemon.notice netifd: LTE (16817): Device does not support 802.3 mode. Informing driver of raw-ip only for wwan0 ..
Fri Jul 28 23:51:51 2023 daemon.notice netifd: LTE (16817): Waiting for network registration
Fri Jul 28 23:51:52 2023 daemon.notice netifd: LTE (16817): Starting network LTE
Fri Jul 28 23:51:52 2023 daemon.notice netifd: LTE (16817): Unable to connect IPv4
Fri Jul 28 23:51:52 2023 daemon.notice netifd: LTE (16926): Stopping network LTE
Fri Jul 28 23:51:52 2023 daemon.notice netifd: LTE (16926): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "LTE" } (Permission denied)
Fri Jul 28 23:51:52 2023 daemon.notice netifd: Interface 'LTE' is now down
Fri Jul 28 23:51:52 2023 daemon.notice netifd: Interface 'LTE' is setting up now
Fri Jul 28 23:51:52 2023 daemon.notice netifd: LTE (16934): Waiting for SIM initialization
Fri Jul 28 23:51:52 2023 daemon.notice netifd: LTE (16934): Failed to parse message data
Fri Jul 28 23:51:53 2023 daemon.notice netifd: LTE (16934): PIN verification is disabled
Fri Jul 28 23:51:53 2023 daemon.notice netifd: LTE (16934): Setting PLMN to 293041
Fri Jul 28 23:51:53 2023 daemon.notice netifd: LTE (16934): Device does not support 802.3 mode. Informing driver of raw-ip only for wwan0 ..
Fri Jul 28 23:51:53 2023 daemon.notice netifd: LTE (16934): Waiting for network registration
Fri Jul 28 23:51:54 2023 daemon.notice netifd: LTE (16934): Starting network LTE
Fri Jul 28 23:51:55 2023 daemon.notice netifd: LTE (16934): Unable to connect IPv4
Fri Jul 28 23:51:55 2023 daemon.notice netifd: LTE (17045): Stopping network LTE
Fri Jul 28 23:51:55 2023 daemon.notice netifd: LTE (17045): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "LTE" } (Permission denied)
Fri Jul 28 23:51:55 2023 daemon.notice netifd: Interface 'LTE' is now down
Fri Jul 28 23:51:55 2023 daemon.notice netifd: Interface 'LTE' is setting up now
Fri Jul 28 23:51:55 2023 daemon.notice netifd: LTE (17053): Waiting for SIM initialization
Fri Jul 28 23:51:55 2023 daemon.notice netifd: LTE (17053): Failed to parse message data
Fri Jul 28 23:51:55 2023 daemon.notice netifd: LTE (17053): PIN verification is disabled
Fri Jul 28 23:51:55 2023 daemon.notice netifd: LTE (17053): Setting PLMN to 293041
Fri Jul 28 23:51:56 2023 daemon.notice netifd: LTE (17053): Device does not support 802.3 mode. Informing driver of raw-ip only for wwan0 ..
Fri Jul 28 23:51:56 2023 daemon.notice netifd: LTE (17053): Waiting for network registration
Fri Jul 28 23:52:08 2023 daemon.notice netifd: LTE (17053): Network registration failed, registration timeout reached
Fri Jul 28 23:52:08 2023 daemon.notice netifd: LTE (17220): Stopping network LTE
Fri Jul 28 23:52:08 2023 daemon.notice netifd: LTE (17220): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "LTE" } (Permission denied)
Fri Jul 28 23:52:08 2023 daemon.notice netifd: Interface 'LTE' is now down

Then I did the serial connection to the modem via Picocom as you asked:

root@OpenWrt:~#  picocom /dev/ttyUSB2
picocom v3.1

port is        : /dev/ttyUSB2
flowcontrol    : none
baudrate is    : 9600
parity is      : none
databits are   : 8
stopbits are   : 1
escape is      : C-a
local echo is  : no
noinit is      : no
noreset is     : no
hangup is      : no
nolock is      : no
send_cmd is    : sz -vv
receive_cmd is : rz -vv -E
imap is        : 
omap is        : 
emap is        : crcrlf,delbs,
logfile is     : none
initstring     : none
exit_after is  : not set
exit is        : no

Type [C-a] [C-h] to see available commands
Terminal ready
AT+CGCONTRDP=1
+CGCONTRDP: 1,5,nodata,10.50.179.116,,,

OK
AT+CGCONTRDP
+CGCONTRDP: 1,5,nodata,10.50.91.162,,,

OK

Now, in the End I have an IPv4 Adress again on the LTE interface, no LTE_4 interface, again not really any RX packets on the LTE interface, and the following showing for ifstatus LTE:

Terminating...
Thanks for using picocom
root@OpenWrt:~# ifstatus LTE
{
        "up": true,
        "pending": false,
        "available": true,
        "autostart": true,
        "dynamic": false,
        "uptime": 21,
        "l3_device": "wwan0",
        "proto": "qmi",
        "updated": [
                "addresses",
                "routes",
                "data"
        ],
        "metric": 0,
        "dns_metric": 0,
        "delegation": true,
        "ipv4-address": [
                {
                        "address": "10.50.89.173",
                        "mask": 30
                }
        ],
        "ipv6-address": [

        ],
        "ipv6-prefix": [

        ],
        "ipv6-prefix-assignment": [

        ],
        "route": [
                {
                        "target": "0.0.0.0",
                        "mask": 0,
                        "nexthop": "10.50.89.174",
                        "source": "0.0.0.0/0"
                }
        ],
        "dns-server": [

        ],
        "dns-search": [

        ],
        "neighbors": [

        ],
        "inactive": {
                "ipv4-address": [

                ],
                "ipv6-address": [

                ],
                "route": [

                ],
                "dns-server": [

                ],
                "dns-search": [

                ],
                "neighbors": [

                ]
        },
        "data": {
                "cid_4": "3",
                "pdh_4": "-2028305568",
                "zone": "wan"
        }
}

Please query your modem from picocom with

ATI
AT+CGDCONT?

Try setting another plmn and see if you still have no DNS servers in ifstatus {your LTE interface name} response.

Hi, sorry for the delay...

I had Error: Unknown error (NETWORK_REGISTRATION_FAILED) in the GUI again.
At this point I restarted the LTE interface via GUI again and got the same error again.

This is the system log from the interface restart:

Sun Jul 30 14:10:41 2023 user.info : luci: accepted login on /admin/network/network for root from 192.168.111.212
Sun Jul 30 14:12:14 2023 daemon.notice netifd: Interface 'LTE' is setting up now
Sun Jul 30 14:12:14 2023 daemon.notice netifd: LTE (16602): Waiting for SIM initialization
Sun Jul 30 14:12:15 2023 daemon.notice netifd: LTE (16602): Failed to parse message data
Sun Jul 30 14:12:15 2023 daemon.notice netifd: LTE (16602): PIN verification is disabled
Sun Jul 30 14:12:15 2023 daemon.notice netifd: LTE (16602): Setting PLMN to 293041
Sun Jul 30 14:12:15 2023 daemon.notice netifd: LTE (16602): Device does not support 802.3 mode. Informing driver of raw-ip only for wwan0 ..
Sun Jul 30 14:12:16 2023 daemon.notice netifd: LTE (16602): Waiting for network registration
Sun Jul 30 14:12:17 2023 daemon.notice netifd: LTE (16602): Starting network LTE
Sun Jul 30 14:12:17 2023 daemon.notice netifd: LTE (16602): Unable to connect IPv4
Sun Jul 30 14:12:17 2023 daemon.notice netifd: LTE (16651): Stopping network LTE
Sun Jul 30 14:12:17 2023 daemon.notice netifd: LTE (16651): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "LTE" } (Permission denied)
Sun Jul 30 14:12:17 2023 daemon.notice netifd: Interface 'LTE' is now down
Sun Jul 30 14:12:17 2023 daemon.notice netifd: Interface 'LTE' is setting up now
Sun Jul 30 14:12:17 2023 daemon.notice netifd: LTE (16659): Waiting for SIM initialization
Sun Jul 30 14:12:17 2023 daemon.notice netifd: LTE (16659): Failed to parse message data
Sun Jul 30 14:12:17 2023 daemon.notice netifd: LTE (16659): PIN verification is disabled
Sun Jul 30 14:12:17 2023 daemon.notice netifd: LTE (16659): Setting PLMN to 293041
Sun Jul 30 14:12:18 2023 daemon.notice netifd: LTE (16659): Device does not support 802.3 mode. Informing driver of raw-ip only for wwan0 ..
Sun Jul 30 14:12:18 2023 daemon.notice netifd: LTE (16659): Waiting for network registration
Sun Jul 30 14:12:19 2023 daemon.notice netifd: LTE (16659): Starting network LTE
Sun Jul 30 14:12:19 2023 daemon.notice netifd: LTE (16659): Unable to connect IPv4
Sun Jul 30 14:12:19 2023 daemon.notice netifd: LTE (16766): Stopping network LTE
Sun Jul 30 14:12:19 2023 daemon.notice netifd: LTE (16766): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "LTE" } (Permission denied)
Sun Jul 30 14:12:19 2023 daemon.notice netifd: Interface 'LTE' is now down
Sun Jul 30 14:12:19 2023 daemon.notice netifd: Interface 'LTE' is setting up now
Sun Jul 30 14:12:19 2023 daemon.notice netifd: LTE (16774): Waiting for SIM initialization
Sun Jul 30 14:12:20 2023 daemon.notice netifd: LTE (16774): Failed to parse message data
Sun Jul 30 14:12:20 2023 daemon.notice netifd: LTE (16774): PIN verification is disabled
Sun Jul 30 14:12:20 2023 daemon.notice netifd: LTE (16774): Setting PLMN to 293041
Sun Jul 30 14:12:20 2023 daemon.notice netifd: LTE (16774): Device does not support 802.3 mode. Informing driver of raw-ip only for wwan0 ..
Sun Jul 30 14:12:21 2023 daemon.notice netifd: LTE (16774): Waiting for network registration
Sun Jul 30 14:12:22 2023 daemon.notice netifd: LTE (16774): Starting network LTE
Sun Jul 30 14:12:22 2023 daemon.notice netifd: LTE (16774): Unable to connect IPv4
Sun Jul 30 14:12:22 2023 daemon.notice netifd: LTE (16880): Stopping network LTE
Sun Jul 30 14:12:22 2023 daemon.notice netifd: LTE (16880): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "LTE" } (Permission denied)
Sun Jul 30 14:12:22 2023 daemon.notice netifd: Interface 'LTE' is now down
Sun Jul 30 14:12:22 2023 daemon.notice netifd: Interface 'LTE' is setting up now
Sun Jul 30 14:12:22 2023 daemon.notice netifd: LTE (16889): Waiting for SIM initialization
Sun Jul 30 14:12:22 2023 daemon.notice netifd: LTE (16889): Failed to parse message data
Sun Jul 30 14:12:22 2023 daemon.notice netifd: LTE (16889): PIN verification is disabled
Sun Jul 30 14:12:22 2023 daemon.notice netifd: LTE (16889): Setting PLMN to 293041
Sun Jul 30 14:12:23 2023 daemon.notice netifd: LTE (16889): Device does not support 802.3 mode. Informing driver of raw-ip only for wwan0 ..
Sun Jul 30 14:12:23 2023 daemon.notice netifd: LTE (16889): Waiting for network registration
Sun Jul 30 14:12:35 2023 daemon.notice netifd: LTE (16889): Network registration failed, registration timeout reached
Sun Jul 30 14:12:35 2023 daemon.notice netifd: LTE (17064): Stopping network LTE
Sun Jul 30 14:12:35 2023 daemon.notice netifd: LTE (17064): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "LTE" } (Permission denied)
Sun Jul 30 14:12:35 2023 daemon.notice netifd: Interface 'LTE' is now down

I dont know if those two messages mean anything in this case?
Sun Jul 30 14:12:20 2023 daemon.notice netifd: LTE (16774): Device does not support 802.3 mode. Informing driver of raw-ip only for wwan0 ..
Sun Jul 30 14:12:22 2023 daemon.notice netifd: LTE (16880): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "LTE" } (Permission denied)

And this is the Picocom commands that you asked for:

root@OpenWrt:~# picocom /dev/ttyUSB2
picocom v3.1

port is        : /dev/ttyUSB2
flowcontrol    : none
baudrate is    : 9600
parity is      : none
databits are   : 8
stopbits are   : 1
escape is      : C-a
local echo is  : no
noinit is      : no
noreset is     : no
hangup is      : no
nolock is      : no
send_cmd is    : sz -vv
receive_cmd is : rz -vv -E
imap is        : 
omap is        : 
emap is        : crcrlf,delbs,
logfile is     : none
initstring     : none
exit_after is  : not set
exit is        : no

Type [C-a] [C-h] to see available commands
Terminal ready
ATI
Quectel
EC25
Revision: EC25EFAR06A11M4G

OK
AT+CGDCONT?
+CGDCONT: 1,"IPV4V6","","0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0",0,0,0,0

OK

Terminating...
Thanks for using picocom

Then I changed the config again, now the new config is:

config interface 'LTE'
        option proto 'qmi'
        option device '/dev/cdc-wdm0'
        option pdptype 'ipv4'
        option autoconnect '1'
        option modes 'lte'
        option apn 'internet.telekom'
        option auth 'none'

I removed the dhcp 0 and the plmn line.

Another restart of the LTE interface via GUI gave me instant connection and the LTE_4 interface back. Still no internet connection though!

Here is the System log from that restart:

Sun Jul 30 14:16:19 2023 daemon.notice netifd: Interface 'LTE' is setting up now
Sun Jul 30 14:16:19 2023 daemon.notice netifd: LTE (17629): Waiting for SIM initialization
Sun Jul 30 14:16:19 2023 daemon.notice netifd: LTE (17629): Failed to parse message data
Sun Jul 30 14:16:20 2023 daemon.notice netifd: LTE (17629): PIN verification is disabled
Sun Jul 30 14:16:20 2023 daemon.notice netifd: LTE (17629): Device does not support 802.3 mode. Informing driver of raw-ip only for wwan0 ..
Sun Jul 30 14:16:20 2023 daemon.notice netifd: LTE (17629): Waiting for network registration
Sun Jul 30 14:16:21 2023 daemon.notice netifd: LTE (17629): Starting network LTE
Sun Jul 30 14:16:21 2023 daemon.notice netifd: LTE (17629): Setting up wwan0
Sun Jul 30 14:16:21 2023 daemon.notice netifd: Interface 'LTE' is now up
Sun Jul 30 14:16:21 2023 daemon.notice netifd: Network device 'wwan0' link is up
Sun Jul 30 14:16:21 2023 daemon.notice netifd: Network alias 'wwan0' link is up
Sun Jul 30 14:16:21 2023 daemon.notice netifd: Interface 'LTE_4' is enabled
Sun Jul 30 14:16:21 2023 daemon.notice netifd: Interface 'LTE_4' has link connectivity
Sun Jul 30 14:16:21 2023 daemon.notice netifd: Interface 'LTE_4' is setting up now
Sun Jul 30 14:16:21 2023 daemon.notice netifd: LTE_4 (17707): udhcpc: started, v1.35.0
Sun Jul 30 14:16:21 2023 daemon.notice netifd: LTE_4 (17707): udhcpc: broadcasting discover
Sun Jul 30 14:16:21 2023 daemon.notice netifd: LTE_4 (17707): udhcpc: broadcasting select for 10.31.191.132, server 10.31.191.133
Sun Jul 30 14:16:21 2023 daemon.notice netifd: LTE_4 (17707): udhcpc: lease of 10.31.191.132 obtained from 10.31.191.133, lease time 7200
Sun Jul 30 14:16:21 2023 user.notice firewall: Reloading firewall due to ifup of LTE (wwan0)
Sun Jul 30 14:16:22 2023 daemon.notice netifd: Interface 'LTE_4' is now up
Sun Jul 30 14:16:22 2023 user.notice firewall: Reloading firewall due to ifup of LTE_4 (wwan0)

And the Picocom:

root@OpenWrt:~# picocom /dev/ttyUSB2
picocom v3.1

port is        : /dev/ttyUSB2
flowcontrol    : none
baudrate is    : 9600
parity is      : none
databits are   : 8
stopbits are   : 1
escape is      : C-a
local echo is  : no
noinit is      : no
noreset is     : no
hangup is      : no
nolock is      : no
send_cmd is    : sz -vv
receive_cmd is : rz -vv -E
imap is        : 
omap is        : 
emap is        : crcrlf,delbs,
logfile is     : none
initstring     : none
exit_after is  : not set
exit is        : no

Type [C-a] [C-h] to see available commands
Terminal ready
ATI
Quectel
EC25
Revision: EC25EFAR06A11M4G

OK
AT+CGDCONT?
+CGDCONT: 1,"IPV4V6","","0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0",0,0,0,0

OK

Terminating...
Thanks for using picocom

and the ifstatus: (LTE)

root@OpenWrt:~# ifstatus LTE
{
        "up": true,
        "pending": false,
        "available": true,
        "autostart": true,
        "dynamic": false,
        "uptime": 474,
        "l3_device": "wwan0",
        "proto": "qmi",
        "updated": [
                "data"
        ],
        "metric": 0,
        "dns_metric": 0,
        "delegation": true,
        "ipv4-address": [

        ],
        "ipv6-address": [

        ],
        "ipv6-prefix": [

        ],
        "ipv6-prefix-assignment": [

        ],
        "route": [

        ],
        "dns-server": [

        ],
        "dns-search": [

        ],
        "neighbors": [

        ],
        "inactive": {
                "ipv4-address": [

                ],
                "ipv6-address": [

                ],
                "route": [

                ],
                "dns-server": [

                ],
                "dns-search": [

                ],
                "neighbors": [

                ]
        },
        "data": {
                "cid_4": "3",
                "pdh_4": "-2028247504"
        }
}

EDIT:
and ifstatus LTE_4:

root@OpenWrt:~# ifstatus LTE_4
{
        "up": true,
        "pending": false,
        "available": true,
        "autostart": true,
        "dynamic": true,
        "uptime": 480,
        "l3_device": "wwan0",
        "proto": "dhcp",
        "device": "wwan0",
        "updated": [
                "addresses",
                "routes",
                "data"
        ],
        "metric": 0,
        "dns_metric": 0,
        "delegation": true,
        "ipv4-address": [
                {
                        "address": "10.31.191.132",
                        "mask": 29
                }
        ],
        "ipv6-address": [

        ],
        "ipv6-prefix": [

        ],
        "ipv6-prefix-assignment": [

        ],
        "route": [
                {
                        "target": "0.0.0.0",
                        "mask": 0,
                        "nexthop": "10.31.191.133",
                        "source": "10.31.191.132/32"
                }
        ],
        "dns-server": [

        ],
        "dns-search": [

        ],
        "neighbors": [

        ],
        "inactive": {
                "ipv4-address": [

                ],
                "ipv6-address": [

                ],
                "route": [

                ],
                "dns-server": [

                ],
                "dns-search": [

                ],
                "neighbors": [

                ]
        },
        "data": {
                "zone": "wan",
                "dhcpserver": "10.31.191.133",
                "hostname": "OpenWrt",
                "leasetime": 7200,
                "zone": "wan"
        }
}

According to uqmi these are the connection settings right now, without any plmn set via the config file:

root@OpenWrt:~# uqmi -d /dev/cdc-wdm0 --get-signal-info --get-serving-system --get-data-status
{
        "type": "lte",
        "rssi": -62,
        "rsrq": -10,
        "rsrp": -86,
        "snr": 19.000000
}
{
        "registration": "registered",
        "plmn_mcc": 293,
        "plmn_mnc": 70,
        "plmn_description": "�\"��\u000c\u000e�",
        "roaming": true
}
"connected"

mnc: 70 is "TELEMACH", before when I had the plmn set via config file I used 41 which is "MOBITEL"

is few years old, I would recommend upgrading the firmware, however, there is no guarantee that this will solve all problems.
Since this modem gets no DNS regardless of the carrier I keep suspecting that something is wrong with the modem itself.

Can you ping from the router any IP address like 8.8.8.8 when you registered to "TELEMACH"?

While still connected to "TELEMACH":

root@OpenWrt:~# ping google.de
ping: bad address 'google.de'
root@OpenWrt:~# ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 56 data bytes
^C
--- 8.8.8.8 ping statistics ---
15 packets transmitted, 0 packets received, 100% packet loss
root@OpenWrt:~# nslookup openwrt.org 8.8.8.8
;; connection timed out; no servers could be reached

-> no ping, no nslookup

Would there be such a difference from a newer firmware just for the usecase of roaming abroad??
Because back at home in Germany it works very well and without problems with "Telekom" Network.

Connection details:

root@OpenWrt:~# uqmi -d /dev/cdc-wdm0 --get-signal-info --get-serving-system --get-data-status
{
        "type": "lte",
        "rssi": -49,
        "rsrq": -9,
        "rsrp": -73,
        "snr": 23.000000
}
{
        "registration": "registered",
        "plmn_mcc": 293,
        "plmn_mnc": 70,
        "plmn_description": "�\"��\u000c\u000e�",
        "roaming": true
}
"connected"
root@OpenWrt:~# ifstatus LTE_4
{
        "up": true,
        "pending": false,
        "available": true,
        "autostart": true,
        "dynamic": true,
        "uptime": 15123,
        "l3_device": "wwan0",
        "proto": "dhcp",
        "device": "wwan0",
        "metric": 0,
        "dns_metric": 0,
        "delegation": true,
        "ipv4-address": [
                {
                        "address": "10.29.188.12",
                        "mask": 29
                }
        ],
        "ipv6-address": [

        ],
        "ipv6-prefix": [

        ],
        "ipv6-prefix-assignment": [

        ],
        "route": [
                {
                        "target": "0.0.0.0",
                        "mask": 0,
                        "nexthop": "10.29.188.13",
                        "source": "10.29.188.12/32"
                }
        ],
        "dns-server": [

        ],
        "dns-search": [

        ],
        "neighbors": [

        ],
        "inactive": {
                "ipv4-address": [

                ],
                "ipv6-address": [

                ],
                "route": [

                ],
                "dns-server": [

                ],
                "dns-search": [

                ],
                "neighbors": [

                ]
        },
        "data": {
                "zone": "wan",
                "dhcpserver": "10.29.188.13",
                "hostname": "OpenWrt",
                "leasetime": 7200,
                "zone": "wan"
        }
}

Try to ping the "nexthop" (gateway) IP. That is the 10.x IP that likely changes every connection. It may be inside the modem (which isn't very useful, you will note it always pings with a time of less than 1 ms) or it is the ISP's first router on the other side of the LTE link.
Then try a traceroute to any numeric IP such as 8.8.8.8. If this goes a few hops into the ISP network then ends, your Internet link is being blocked by their policies.

Do you have DNS server address statically configured on the laptop?
To pass the connection test, the Windows machine first needs to resolve www.msftconnecttest.com, which is impossible without a working DNS.

Please do this to test one of my guesses:

AT+QMBNCFG="AutoSel"
AT+QMBNCFG="List"

This is the current connection info, ping to nexthop and traceroute:

root@OpenWrt:~# ifstatus LTE_4
{
        "up": true,
        "pending": false,
        "available": true,
        "autostart": true,
        "dynamic": true,
        "uptime": 39,
        "l3_device": "wwan0",
        "proto": "dhcp",
        "device": "wwan0",
        "updated": [
                "addresses",
                "routes",
                "data"
        ],
        "metric": 0,
        "dns_metric": 0,
        "delegation": true,
        "ipv4-address": [
                {
                        "address": "10.32.198.227",
                        "mask": 29
                }
        ],
        "ipv6-address": [

        ],
        "ipv6-prefix": [

        ],
        "ipv6-prefix-assignment": [

        ],
        "route": [
                {
                        "target": "0.0.0.0",
                        "mask": 0,
                        "nexthop": "10.32.198.228",
                        "source": "10.32.198.227/32"
                }
        ],
        "dns-server": [

        ],
        "dns-search": [

        ],
        "neighbors": [

        ],
        "inactive": {
                "ipv4-address": [

                ],
                "ipv6-address": [

                ],
                "route": [

                ],
                "dns-server": [

                ],
                "dns-search": [

                ],
                "neighbors": [

                ]
        },
        "data": {
                "zone": "wan",
                "dhcpserver": "10.32.198.228",
                "hostname": "OpenWrt",
                "leasetime": 7200,
                "zone": "wan"
        }
}
root@OpenWrt:~# ping 10.32.198.228
PING 10.32.198.228 (10.32.198.228): 56 data bytes
^C
--- 10.32.198.228 ping statistics ---
7 packets transmitted, 0 packets received, 100% packet loss
root@OpenWrt:~# traceroute 8.8.8.8
traceroute to 8.8.8.8 (8.8.8.8), 30 hops max, 46 byte packets
 1  *  *  *
 2  *  *  *
 3  *  *  *
 4  *  *  *
 5  *  *  *
 6  *  *  *
 7  *  *  *
 8  *  *  *
 9  *  *  *
10  *  *  *
11^C
root@OpenWrt:~# picocom /dev/ttyUSB2
picocom v3.1

port is        : /dev/ttyUSB2
flowcontrol    : none
baudrate is    : 9600
parity is      : none
databits are   : 8
stopbits are   : 1
escape is      : C-a
local echo is  : no
noinit is      : no
noreset is     : no
hangup is      : no
nolock is      : no
send_cmd is    : sz -vv
receive_cmd is : rz -vv -E
imap is        : 
omap is        : 
emap is        : crcrlf,delbs,
logfile is     : none
initstring     : none
exit_after is  : not set
exit is        : no

Type [C-a] [C-h] to see available commands
Terminal ready
AT+QMBNCFG="AutoSel"
+QMBNCFG: "AutoSel",0

OK
AT+QMBNCFG="List"
+QMBNCFG: "List",0,0,0,"ROW_Generic_3GPP",0x05010824,201806201
+QMBNCFG: "List",1,0,0,"Reliance_OpnMkt",0x05011B4B,201801051
+QMBNCFG: "List",2,0,0,"TW_Mobile_China_VoLTE",0x05800301,202005121
+QMBNCFG: "List",3,0,0,"Bouygues_France_VoLTE",0x05800101,202004151
+QMBNCFG: "List",4,0,0,"Telstra-Commercial_VoLTE",0x05800716,202002061
+QMBNCFG: "List",5,0,0,"Commercial-Smartfren",0x05012509,202001041
+QMBNCFG: "List",6,0,0,"VF_Germany_VoLTE",0x05010444,202005121
+QMBNCFG: "List",7,0,0,"Swis_switzerland_VoLTE_VoWiFi",0x05010421,201712231
+QMBNCFG: "List",8,0,0,"TF_Spain_VoLTE",0x05800D43,201909301
+QMBNCFG: "List",9,0,0,"Commercial-DT-VOLTE",0x05011F27,202006291
+QMBNCFG: "List",10,0,0,"STC_Saudi_VoLTE",0x0501FE24,202002271

OK

Terminating...
Thanks for using picocom

After the changes above it wont make a connection again as before.

This is from system log:

Tue Aug  1 19:42:20 2023 daemon.notice netifd: Interface 'LTE' is now down
Tue Aug  1 19:42:20 2023 daemon.notice netifd: Interface 'LTE' is setting up now
Tue Aug  1 19:42:20 2023 daemon.notice netifd: LTE (3781): Waiting for SIM initialization
Tue Aug  1 19:42:20 2023 daemon.notice netifd: LTE (3781): Failed to parse message data
Tue Aug  1 19:42:20 2023 daemon.notice netifd: LTE (3781): PIN verification is disabled
Tue Aug  1 19:42:21 2023 daemon.notice netifd: LTE (3781): Device does not support 802.3 mode. Informing driver of raw-ip only for wwan0 ..
Tue Aug  1 19:42:21 2023 daemon.notice netifd: LTE (3781): Waiting for network registration
Tue Aug  1 19:42:22 2023 daemon.notice netifd: LTE (3781): Starting network LTE
Tue Aug  1 19:42:22 2023 daemon.notice netifd: LTE (3781): Unable to connect IPv4
Tue Aug  1 19:42:22 2023 daemon.notice netifd: LTE (3890): Stopping network LTE
Tue Aug  1 19:42:22 2023 daemon.notice netifd: LTE (3890): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "LTE" } (Permission denied)
Tue Aug  1 19:42:22 2023 daemon.notice netifd: Interface 'LTE' is now down
Tue Aug  1 19:42:22 2023 daemon.notice netifd: Interface 'LTE' is setting up now
Tue Aug  1 19:42:22 2023 daemon.notice netifd: LTE (3898): Waiting for SIM initialization
Tue Aug  1 19:42:23 2023 daemon.notice netifd: LTE (3898): Failed to parse message data
Tue Aug  1 19:42:23 2023 daemon.notice netifd: LTE (3898): PIN verification is disabled
Tue Aug  1 19:42:23 2023 daemon.notice netifd: LTE (3898): Device does not support 802.3 mode. Informing driver of raw-ip only for wwan0 ..
Tue Aug  1 19:42:23 2023 daemon.notice netifd: LTE (3898): Waiting for network registration
Tue Aug  1 19:42:25 2023 daemon.notice netifd: LTE (3898): Starting network LTE
Tue Aug  1 19:42:25 2023 daemon.notice netifd: LTE (3898): Unable to connect IPv4
Tue Aug  1 19:42:25 2023 daemon.notice netifd: LTE (4003): Stopping network LTE
Tue Aug  1 19:42:25 2023 daemon.notice netifd: LTE (4003): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "LTE" } (Permission denied)
Tue Aug  1 19:42:25 2023 daemon.notice netifd: Interface 'LTE' is now down
Tue Aug  1 19:42:25 2023 daemon.notice netifd: Interface 'LTE' is setting up now
Tue Aug  1 19:42:25 2023 daemon.notice netifd: LTE (4011): Waiting for SIM initialization
Tue Aug  1 19:42:25 2023 daemon.notice netifd: LTE (4011): Failed to parse message data
Tue Aug  1 19:42:25 2023 daemon.notice netifd: LTE (4011): PIN verification is disabled
Tue Aug  1 19:42:25 2023 daemon.notice netifd: LTE (4011): Device does not support 802.3 mode. Informing driver of raw-ip only for wwan0 ..
Tue Aug  1 19:42:26 2023 daemon.notice netifd: LTE (4011): Waiting for network registration
Tue Aug  1 19:42:27 2023 daemon.notice netifd: LTE (4011): Starting network LTE
Tue Aug  1 19:42:27 2023 daemon.notice netifd: LTE (4011): Unable to connect IPv4
Tue Aug  1 19:42:27 2023 daemon.notice netifd: LTE (4117): Stopping network LTE
Tue Aug  1 19:42:27 2023 daemon.notice netifd: LTE (4117): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "LTE" } (Permission denied)
Tue Aug  1 19:42:27 2023 daemon.notice netifd: Interface 'LTE' is now down
Tue Aug  1 19:42:27 2023 daemon.notice netifd: Interface 'LTE' is setting up now

I asked this before, but these two error messages have nothing to do with the current problem?

Tue Aug  1 19:42:23 2023 daemon.notice netifd: LTE (3898): Device does not support 802.3 mode. Informing driver of raw-ip only for wwan0 ..
Tue Aug  1 19:42:22 2023 daemon.notice netifd: LTE (3890): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "LTE" } (Permission denied)

This seems very unlikely to me, since when I tested about a week ago the SIM card in my mobile phone is was working without problems!

And also when not beeing abroad and having to roam in a different network it worked fine. My Home Network in Germany is "Telekom".

Log messages you mentioned are normal.