No Wifi signal - Unifi

I have the following small and simple motel client that I need a solution for:

Small motel (10 rooms)
Two UAP-AC-M APs (1 - 2 yrs old)
No USG, just ISPs router - has been working fine
Unifi Controller on office PC - no captive portals or VLANs so only run when I am there
APs showing on Controller as running perfectly - blue light on side of APs as well
No updates pending
This last week, no signal being broadcast from either one
Rebooted both, signal popped up for about two minutes, phone connected automatically, then signals      disappeared.

Ideas, thoughts?

Check the configuration, check the controller logs for errors.

Check for WiFi band interference, I’ve seen it make APs look offline, but not very common.