Can't connect cisco AP to CISCO controller, where to dig?

Question

Cisco

Hello! Unable to connect cisco AP to CISCO controller.
With such a scheme, what can be done?

Answer 1

before the point was connected?
which access point?
and controller version?
Are there enough licenses on the controller?
Is the dns entry correct for the CISCO-LWAPP-CONTROLLER
access point? Is there access from the point to the controller
and from the logs from the point and the controller, you can tell the reason for not connecting.