For the record, an update on this issue. I set my ISP router to assign ULAs, but that made no difference. I could find no way to get to the web interface for the C7, so I did a factory reset, and...

Thanks Almaretto, To be honest, I don't know much about IPv6. Everything is on the same IPv4 subnet. The IPv6 settings on my main router are the defaults. It is set to "Assign unique local addresses...

Model : Hardware Version : Not Clear Firmware Version : ISP : I just bought an Archer C7, which I've set up as an AP. This works fine - devices can connect to it and access the internet through my...