@Liverpool20 yep, in theory that would be true. That's why I think it's a firmware issue.

Ok must have been a bug in the AX1800. I toggled the access control and IP/MAC binding settings and it started working. So frustrating. Am reporting so that the next guy can try this “fix.”

I have an AX1800 router connected to my Xfinity modem. Works great, no problems. I have an Archer A20 in my study connected by Ethernet to the AX1800 router. The A20 runs in access point (AP) mode....