My assumption is that the AP is not "fully" connected.
So let's check for that...please do the following....
- set the log level to informational in the GUI > Controller > Logs > Logs Configuration > Wireless Controller Log Level:
- disconnect the AP from the port/power
- reconnect the AP
- check the log (GUI > logs > EWC: Events > All), is the last message that you get "Blacklist successfully sent..." like in the screenshot below.- if not please post a screenshot.