Please excuse when I'm missing the obvious. I have an AC50 and a couple of CAP1750 and CAP300 in my network. They worked fine in the past, but something must have changed. Recently, the the AP don't show up in the AC50 anymore. Accessing the internet over the network still works. The LED on all AP is green but flashes.

Some of of the AP are directly connected to the AC50, some are connected to an PoE switch - all show the same behaviour.

I've tried already to change DHCP from "AP only" to "AP and client" - no difference.

I've tried rebooting all AP - no difference.

I've power-cycling an AP - did not make a difference.

I've disconnected the AC50 from the internet router (and the DHCP server running there) - no difference.

I'm running out of ideas what might be causing this or how to analyze this, and would be happy to get any suggestions.

Dadof4