New Unifi AP cannot list on Unifi controller

Reason: DNS not locate unifi="your Unifi controller IP address"

Fix : use SSH(e.g. Putty) connect AP ip address, enter default user name(ubnt) and password (ubnt)

key in : set-inform http://<'your Unifi controller ip address'>:8080/inform

E.g.
set-inform http://192.168.1.10:8080/inform