3G Dongle: LCP: timeout sending Config-Requests

Hi! I am trying to get a 3G dongle working. I tried it with OpenWRT 17.01.5 and now with 18.06 with same result.

The modem is recognized correctly, and CHAT connects, but finally I get a ppp error: ** LCP: timeout sending Config-Requests**

My router is a Huaweii HG556a version B. My dongle is a Huawei is a K3770.

In some forum I read that this problem is because I don't have the module nf_conntrack_pptp module . But I think this is a built-in module and have to be enabled in compile process, isn't it? Could it be the problem?

Thanks

Full log

Sun Jun  9 15:40:50 2019 local2.info chat[1533]: abort on (BUSY)
Sun Jun  9 15:40:50 2019 local2.info chat[1533]: abort on (NO CARRIER)
Sun Jun  9 15:40:50 2019 local2.info chat[1533]: abort on (ERROR)
Sun Jun  9 15:40:50 2019 local2.info chat[1533]: report (CONNECT)
Sun Jun  9 15:40:50 2019 local2.info chat[1533]: timeout set to 10 seconds
Sun Jun  9 15:40:50 2019 local2.info chat[1533]: send (AT&F^M)
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: expect (OK)
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: ^M
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: ^MODE: 5,4^M
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: ^M
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: ^RSSI: 8^M
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: AT&F^M^M
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: OK
Sun Jun  9 15:40:51 2019 local2.info chat[1533]:  -- got it
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: send (ATE1^M)
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: expect (OK)
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: ^M
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: ATE1^M^M
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: OK
Sun Jun  9 15:40:51 2019 local2.info chat[1533]:  -- got it
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: send (AT+CGDCONT=1,"IP","gprs.pepephone.com"^M)
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: timeout set to 30 seconds
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: expect (OK)
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: ^M
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: AT+CGDCONT=1,"IP","gprs.pepephone.com"^M^M
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: OK
Sun Jun  9 15:40:51 2019 local2.info chat[1533]:  -- got it
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: send (ATD*99#^M)
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: expect (CONNECT)
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: ^M
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: ATD*99#^M^M
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: CONNECT
Sun Jun  9 15:40:51 2019 local2.info chat[1533]:  -- got it
Sun Jun  9 15:40:51 2019 local2.info chat[1533]: send ( ^M)
Sun Jun  9 15:40:51 2019 daemon.info pppd[1512]: Serial connection established.
Sun Jun  9 15:40:51 2019 kern.info kernel: [   59.598117] 3g-LTE: renamed from ppp0
Sun Jun  9 15:40:51 2019 daemon.info pppd[1512]: Using interface 3g-LTE
Sun Jun  9 15:40:51 2019 daemon.notice pppd[1512]: Connect: 3g-LTE <--> /dev/ttyUSB2
Sun Jun  9 15:40:53 2019 daemon.info dnsmasq[1518]: read /etc/hosts - 4 addresses
Sun Jun  9 15:40:53 2019 daemon.info dnsmasq[1518]: read /tmp/hosts/dhcp.cfg01411c - 2 addresses
Sun Jun  9 15:40:53 2019 daemon.info dnsmasq-dhcp[1518]: read /etc/ethers - 0 addresses
Sun Jun  9 15:41:22 2019 daemon.warn pppd[1512]: LCP: timeout sending Config-Requests
Sun Jun  9 15:41:22 2019 daemon.notice pppd[1512]: Connection terminated.
Sun Jun  9 15:41:24 2019 daemon.notice pppd[1512]: Modem hangup
Sun Jun  9 15:41:24 2019 daemon.info pppd[1512]: Exit.

With this dongle, could I use any other mode different from ppp? QMI, NCM, RNDIS...?

Did you ever got his sorted?
I've got same problem on my E3372

You should not use PPP with E3372. Make sure you're running 21.X firmware and use NCM.

I used NCM initially but I was not able to connect. Hence move to PPP for debugging.

This is what I am getting after enabling debug on PPP

Mon Oct 12 16:39:49 2020 daemon.notice pppd[2447]: pppd 2.4.7 started by root, uid 0
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: abort on (BUSY)
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: abort on (NO CARRIER)
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: abort on (ERROR)
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: report (CONNECT)
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: timeout set to 10 seconds
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: send (AT&F^M)
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: expect (OK)
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: AT&F^M^M
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: OK
Mon Oct 12 16:39:50 2020 local2.info chat[2449]:  -- got it
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: send (ATE1^M)
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: expect (OK)
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: ^M
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: ATE1^M^M
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: OK
Mon Oct 12 16:39:50 2020 local2.info chat[2449]:  -- got it
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: send (AT+CGDCONT=1,"IP",""^M)
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: timeout set to 30 seconds
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: expect (OK)
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: ^M
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: AT+CGDCONT=1,"IP",""^M^M
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: OK
Mon Oct 12 16:39:50 2020 local2.info chat[2449]:  -- got it
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: send (ATD*99***1#^M)
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: expect (CONNECT)
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: ^M
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: ATD*99***1#^M^M
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: CONNECT
Mon Oct 12 16:39:50 2020 local2.info chat[2449]:  -- got it
Mon Oct 12 16:39:50 2020 local2.info chat[2449]: send ( ^M)
Mon Oct 12 16:39:50 2020 daemon.debug pppd[2447]: Script DIALNUMBER=*99***1# /usr/sbin/chat -t5 -v -E -f /etc/chatscripts/3g.chat finished (pid 2448), status = 0x0
Mon Oct 12 16:39:50 2020 daemon.info pppd[2447]: Serial connection established.
Mon Oct 12 16:39:50 2020 daemon.debug pppd[2447]: using channel 14
Mon Oct 12 16:39:50 2020 kern.info kernel: [  842.253490] 3g-wan: renamed from ppp0
Mon Oct 12 16:39:51 2020 daemon.info pppd[2447]: Using interface 3g-wan
Mon Oct 12 16:39:51 2020 daemon.notice pppd[2447]: Connect: 3g-wan <--> /dev/ttyUSB1
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x479cb0b7>]
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: rcvd [LCP ConfReq id=0x1 <accomp> <pcomp> <asyncmap 0x0> <mru 1500> <magic 0x551> <auth chap MD5>]
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: No auth is possible
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: sent [LCP ConfRej id=0x1 <accomp> <pcomp> <auth chap MD5>]
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x479cb0b7>]
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: rcvd [LCP ConfReq id=0x2 <asyncmap 0x0> <mru 1500> <magic 0x551>]
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: sent [LCP ConfAck id=0x2 <asyncmap 0x0> <mru 1500> <magic 0x551>]
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0x0 magic=0x479cb0b7]
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: sent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: sent [IPV6CP ConfReq id=0x1 <addr fe80::2413:1412:d903:7c02>]
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0x0 magic=0x551]
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfReq id=0x1]
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: sent [IPCP ConfNak id=0x1 <addr 0.0.0.0>]
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: rcvd [LCP ProtRej id=0x3 80 57 01 01 00 0e 01 0a 24 13 14 12 d9 03 7c 02]
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: Protocol-Reject for 'IPv6 Control Protocol' (0x8057) received
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfNak id=0x1 <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: sent [IPCP ConfReq id=0x2 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfReq id=0x2]
Mon Oct 12 16:39:52 2020 daemon.debug pppd[2447]: sent [IPCP ConfAck id=0x2]
Mon Oct 12 16:39:53 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0x1 magic=0x479cb0b7]
Mon Oct 12 16:39:53 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0x1 magic=0x551]
Mon Oct 12 16:39:53 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfNak id=0x2 <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:39:53 2020 daemon.debug pppd[2447]: sent [IPCP ConfReq id=0x3 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:39:54 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0x2 magic=0x479cb0b7]
Mon Oct 12 16:39:54 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0x2 magic=0x551]
Mon Oct 12 16:39:55 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0x3 magic=0x479cb0b7]
Mon Oct 12 16:39:55 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0x3 magic=0x551]
Mon Oct 12 16:39:55 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfNak id=0x3 <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:39:55 2020 daemon.debug pppd[2447]: sent [IPCP ConfReq id=0x4 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:39:56 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0x4 magic=0x479cb0b7]
Mon Oct 12 16:39:56 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0x4 magic=0x551]
Mon Oct 12 16:39:56 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfNak id=0x4 <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:39:56 2020 daemon.debug pppd[2447]: sent [IPCP ConfReq id=0x5 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:39:57 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0x5 magic=0x479cb0b7]
Mon Oct 12 16:39:57 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0x5 magic=0x551]
Mon Oct 12 16:39:58 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0x6 magic=0x479cb0b7]
Mon Oct 12 16:39:58 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0x6 magic=0x551]
Mon Oct 12 16:39:58 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfReq id=0x3]
Mon Oct 12 16:39:58 2020 daemon.debug pppd[2447]: sent [IPCP ConfAck id=0x3]
Mon Oct 12 16:39:58 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfNak id=0x5 <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:39:58 2020 daemon.debug pppd[2447]: sent [IPCP ConfReq id=0x6 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:39:59 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0x7 magic=0x479cb0b7]
Mon Oct 12 16:39:59 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0x7 magic=0x551]
Mon Oct 12 16:39:59 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfNak id=0x6 <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:39:59 2020 daemon.debug pppd[2447]: sent [IPCP ConfReq id=0x7 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:00 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0x8 magic=0x479cb0b7]
Mon Oct 12 16:40:00 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0x8 magic=0x551]
Mon Oct 12 16:40:01 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0x9 magic=0x479cb0b7]
Mon Oct 12 16:40:01 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0x9 magic=0x551]
Mon Oct 12 16:40:01 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfNak id=0x7 <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:01 2020 daemon.debug pppd[2447]: sent [IPCP ConfReq id=0x8 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:02 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0xa magic=0x479cb0b7]
Mon Oct 12 16:40:02 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0xa magic=0x551]
Mon Oct 12 16:40:02 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfNak id=0x8 <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:02 2020 daemon.debug pppd[2447]: sent [IPCP ConfReq id=0x9 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:03 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0xb magic=0x479cb0b7]
Mon Oct 12 16:40:03 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0xb magic=0x551]
Mon Oct 12 16:40:04 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfReq id=0x4]
Mon Oct 12 16:40:04 2020 daemon.debug pppd[2447]: sent [IPCP ConfAck id=0x4]
Mon Oct 12 16:40:04 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0xc magic=0x479cb0b7]
Mon Oct 12 16:40:04 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0xc magic=0x551]
Mon Oct 12 16:40:04 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfNak id=0x9 <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:04 2020 daemon.debug pppd[2447]: sent [IPCP ConfReq id=0xa <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:05 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0xd magic=0x479cb0b7]
Mon Oct 12 16:40:05 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0xd magic=0x551]
Mon Oct 12 16:40:05 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfNak id=0xa <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:05 2020 daemon.debug pppd[2447]: sent [IPCP ConfReq id=0xb <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:06 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0xe magic=0x479cb0b7]
Mon Oct 12 16:40:06 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0xe magic=0x551]
Mon Oct 12 16:40:07 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0xf magic=0x479cb0b7]
Mon Oct 12 16:40:07 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0xf magic=0x551]
Mon Oct 12 16:40:07 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfNak id=0xb <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:07 2020 daemon.debug pppd[2447]: sent [IPCP ConfReq id=0xc <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:08 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0x10 magic=0x479cb0b7]
Mon Oct 12 16:40:08 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0x10 magic=0x551]
Mon Oct 12 16:40:08 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfNak id=0xc <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:08 2020 daemon.debug pppd[2447]: sent [IPCP ConfReq id=0xd <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:09 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0x11 magic=0x479cb0b7]
Mon Oct 12 16:40:09 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0x11 magic=0x551]
Mon Oct 12 16:40:10 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfReq id=0x5]
Mon Oct 12 16:40:10 2020 daemon.debug pppd[2447]: sent [IPCP ConfAck id=0x5]
Mon Oct 12 16:40:10 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0x12 magic=0x479cb0b7]
Mon Oct 12 16:40:10 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0x12 magic=0x551]
Mon Oct 12 16:40:10 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfNak id=0xd <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:10 2020 daemon.debug pppd[2447]: sent [IPCP ConfReq id=0xe <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:11 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0x13 magic=0x479cb0b7]
Mon Oct 12 16:40:11 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0x13 magic=0x551]
Mon Oct 12 16:40:11 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfNak id=0xe <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:11 2020 daemon.debug pppd[2447]: sent [IPCP ConfReq id=0xf <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:12 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0x14 magic=0x479cb0b7]
Mon Oct 12 16:40:12 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0x14 magic=0x551]
Mon Oct 12 16:40:13 2020 daemon.debug pppd[2447]: sent [LCP EchoReq id=0x15 magic=0x479cb0b7]
Mon Oct 12 16:40:13 2020 daemon.debug pppd[2447]: rcvd [LCP EchoRep id=0x15 magic=0x551]
Mon Oct 12 16:40:13 2020 daemon.debug pppd[2447]: rcvd [IPCP ConfNak id=0xf <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:40:13 2020 daemon.debug pppd[2447]: sent [IPCP ConfReq id=0x10 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]

Looks like the modem never gets WAN IP address if I read it correctly.

Mind you - when I put different SIM card (LTE - 4g) I am able to connect to LTE network. The connection fails to get established for when only UMTS (3g) network is available - for both cards.

Here is a PPP log for LTE connection (same modem, same router):

Mon Oct 12 16:05:13 2020 daemon.notice pppd[1312]: pppd 2.4.7 started by root, uid 0
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: abort on (BUSY)
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: abort on (NO CARRIER)
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: abort on (ERROR)
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: report (CONNECT)
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: timeout set to 10 seconds
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: send (AT&F^M)
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: expect (OK)
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: AT&F^M^M
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: OK
Mon Oct 12 16:05:15 2020 local2.info chat[1391]:  -- got it
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: send (ATE1^M)
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: expect (OK)
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: ^M
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: ATE1^M^M
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: OK
Mon Oct 12 16:05:15 2020 local2.info chat[1391]:  -- got it
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: send (AT+CGDCONT=1,"IP",""^M)
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: timeout set to 30 seconds
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: expect (OK)
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: ^M
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: AT+CGDCONT=1,"IP",""^M^M
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: OK
Mon Oct 12 16:05:15 2020 local2.info chat[1391]:  -- got it
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: send (ATD*99***1#^M)
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: expect (CONNECT)
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: ^M
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: ATD*99***1#^M^M
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: CONNECT
Mon Oct 12 16:05:15 2020 local2.info chat[1391]:  -- got it
Mon Oct 12 16:05:15 2020 local2.info chat[1391]: send ( ^M)
Mon Oct 12 16:05:15 2020 daemon.debug pppd[1312]: Script DIALNUMBER=*99***1# /usr/sbin/chat -t5 -v -E -f /etc/chatscripts/3g.chat finished (pid 1384), status = 0x0
Mon Oct 12 16:05:15 2020 daemon.info pppd[1312]: Serial connection established.
Mon Oct 12 16:05:15 2020 daemon.debug pppd[1312]: using channel 1
Mon Oct 12 16:05:15 2020 kern.info kernel: [   33.184806] 3g-wan: renamed from ppp0
Mon Oct 12 16:05:15 2020 daemon.info pppd[1312]: Using interface 3g-wan
Mon Oct 12 16:05:15 2020 daemon.notice pppd[1312]: Connect: 3g-wan <--> /dev/ttyUSB1
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x6ee6776f>]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: rcvd [LCP ConfReq id=0x1 <accomp> <pcomp> <asyncmap 0x0> <mru 1500> <magic 0x543> <auth chap MD5>]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: No auth is possible
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: sent [LCP ConfRej id=0x1 <accomp> <pcomp> <auth chap MD5>]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x6ee6776f>]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: rcvd [LCP ConfReq id=0x2 <asyncmap 0x0> <mru 1500> <magic 0x543>]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: sent [LCP ConfAck id=0x2 <asyncmap 0x0> <mru 1500> <magic 0x543>]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: sent [LCP EchoReq id=0x0 magic=0x6ee6776f]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: sent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: sent [IPV6CP ConfReq id=0x1 <addr fe80::e8a6:006a:bd09:2d7a>]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: rcvd [LCP EchoRep id=0x0 magic=0x543]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: rcvd [IPCP ConfReq id=0x1]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: sent [IPCP ConfNak id=0x1 <addr 0.0.0.0>]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: rcvd [LCP ProtRej id=0x3 80 57 01 01 00 0e 01 0a e8 a6 00 6a bd 09 2d 7a]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: Protocol-Reject for 'IPv6 Control Protocol' (0x8057) received
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: rcvd [IPCP ConfNak id=0x1 <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: sent [IPCP ConfReq id=0x2 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: rcvd [IPCP ConfReq id=0x2]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: sent [IPCP ConfAck id=0x2]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: rcvd [IPCP ConfNak id=0x2 <addr 100.83.22.127> <ms-dns1 212.2.127.254> <ms-dns2 212.2.96.52>]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: sent [IPCP ConfReq id=0x3 <addr 100.83.22.127> <ms-dns1 212.2.127.254> <ms-dns2 212.2.96.52>]
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: rcvd [IPCP ConfAck id=0x3 <addr 100.83.22.127> <ms-dns1 212.2.127.254> <ms-dns2 212.2.96.52>]
Mon Oct 12 16:05:17 2020 daemon.warn pppd[1312]: Could not determine remote IP address: defaulting to 10.64.64.64
Mon Oct 12 16:05:17 2020 daemon.notice pppd[1312]: local  IP address 100.83.22.127
Mon Oct 12 16:05:17 2020 daemon.notice pppd[1312]: remote IP address 10.64.64.64
Mon Oct 12 16:05:17 2020 daemon.notice pppd[1312]: primary   DNS address 212.2.127.254
Mon Oct 12 16:05:17 2020 daemon.notice pppd[1312]: secondary DNS address 212.2.96.52
Mon Oct 12 16:05:17 2020 daemon.debug pppd[1312]: Script /lib/netifd/ppp-up started (pid 1473)
Mon Oct 12 16:05:17 2020 daemon.notice netifd: Network device 'wlan0' link is up
Mon Oct 12 16:05:17 2020 daemon.notice netifd: Network device '3g-wan' link is up
Mon Oct 12 16:05:17 2020 daemon.notice netifd: Interface 'wan' is now up

?

Please switch to NCM and start a new topic if your problem persists.
Don't forget to set the APN - it is currently missing.