@vcunat You might be just right.
I just checked with my other modem that acts like a small router; connecting via DHCP and ‘double NAT’. And when I check_connection on it it’s fine. Everything works except IPv6 but that’s fine I just get IPv4 from ISP.
I will try to check some more and update here…
Here is topic where I explain my -strange someone might say- way to access the Internets.
EDIT: Yup I just checked it seems like an error comes from a (not yet!)-supported protocol. I thought it’s related to that, that my WAN was set on different interface name but if it’s on wan it’s the same problem.
config interface 'wan'
option ifname 'wan'
[...]
option proto 'ncm'
[...]