Router has ipv6 address, but no route

My isp should provide ipv6 over PPPoE. The isp modem is set to bridge mode and PPPoE is handled by my router. I have no problem with ipv4.

The router somehow obtained an ipv6 prefix from my isp with the wan6 interface being down all times. And lan has the address 2408:8207:2427:xxxx::1/60. The client also gets their own ipv6 in that range. However, there is no connectivity. Pinging any ipv6 address on the internet shows ping: sendto: Network unreachable. Inside the network, ipv6 works fine. Is this a problem on my side, or should I call my isp? Thanks in advance.

root@MiRouter:~# ip -6 route
default from 2408:8206:2422:caxx::/64 via fe80::cecc:81ff:fec0:9694 dev pppoe-wan proto static metric 512 pref medium
default from 2408:8207:2427:xxxx::/60 via fe80::cecc:81ff:fec0:9694 dev pppoe-wan proto static metric 512 pref medium
2408:8206:2422:ca37::/64 dev pppoe-wan proto static metric 256 pref medium
2408:8207:2427:xxxx::/64 dev br-lan proto static metric 1024 pref medium
unreachable 2408:8207:2427:xxxx::/60 dev lo proto static metric 2147483647 error 4294967148 pref medium
fe80::/64 dev eth0 proto kernel metric 256 pref medium
fe80::/64 dev br-lan proto kernel metric 256 pref medium
fe80::/64 dev wlan1 proto kernel metric 256 pref medium
fe80::/64 dev wlan0 proto kernel metric 256 pref medium
fe80::/64 dev wlan1-1 proto kernel metric 256 pref medium
fe80::/64 dev eth0.2 proto kernel metric 256 pref medium
fe80::/10 dev pppoe-wan metric 1 pref medium
fe80::/10 dev pppoe-wan proto kernel metric 256 pref medium
root@MiRouter:~# ifstatus wan
{
        "up": true,
        "pending": false,
        "available": true,
        "autostart": true,
        "dynamic": false,
        "uptime": 7655,
        "l3_device": "pppoe-wan",
        "proto": "pppoe",
        "device": "eth0.2",
        "updated": [
                "addresses",
                "routes"
        ],
        "metric": 0,
        "dns_metric": 0,
        "delegation": true,
        "ipv4-address": [
                {
                        "address": "221.221.219.xxx",
                        "mask": 32,
                        "ptpaddress": "221.221.216.1"
                }
        ],
        "ipv6-address": [
                {
                        "address": "fe80::217d:1b98:65b1:cfaa",
                        "mask": 128
                }
        ],
        "ipv6-prefix": [

        ],
        "ipv6-prefix-assignment": [

        ],
        "route": [
                {
                        "target": "0.0.0.0",
                        "mask": 0,
                        "nexthop": "221.221.216.1",
                        "source": "0.0.0.0/0"
                }
        ],
        "dns-server": [
                "202.106.46.151",
                "202.106.195.68"
        ],
        "dns-search": [

        ],
        "neighbors": [

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

                ],
                "ipv6-address": [

                ],
                "route": [

                ],
                "dns-server": [

                ],
                "dns-search": [

                ],
                "neighbors": [

                ]
        },
        "data": {

        }
}

I also found this in the logs:

hu May 26 17:26:18 2022 daemon.notice netifd: Interface 'wan6' is now down
Thu May 26 17:26:18 2022 daemon.notice netifd: Interface 'wan6' is setting up now
Thu May 26 17:26:18 2022 daemon.err odhcpd[1373]: setsockopt(PACKET_ADD_MEMBERSHIP): Invalid argument
Thu May 26 17:26:19 2022 daemon.warn odhcpd[1373]: A default route is present but there is no public prefix on lan thus we don't announce a default route!

Please run the following commands (copy-paste the whole block) and paste the output here, using the "Preformatted text </> " button:
grafik
Remember to redact passwords, MAC addresses and any public IP addresses you may have

ubus call system board; \
uci export network; uci export dhcp; uci export firewall; \
head -n -0 /etc/firewall.user; \
ip -6 addr ; ip -6 ro li tab all ; ip -6 ru; \
ls -l  /etc/resolv.* /tmp/resolv.* /tmp/resolv.*/* ; head -n -0 /etc/resolv.* /tmp/resolv.* /tmp/resolv.*/* ; \
ifstatus wan6