ap fails to join WLC [dtls_disconnect: ERROR shutting down]

[JustTakeTheFirstStep]

Hi.

ap fails to join WLC

WLC : 5508

AP : 2802

Ping is no problem.

WLC time is my current time.
The time between WLC and AP seems to be different, but does it matter?

I will attach AP and WLC logs.

What is the problem ??

-AP LOG-

May 9 04:49:16 kernel: [*05/09/2020 04:49:16.0551] CAPWAP State: Discovery
May 9 04:49:16 kernel: [*05/09/2020 04:49:16.0574] Discovery Request sent to 172.20.201.9, discovery type STATIC_CONFIG(1)
May 9 04:49:16 kernel: [*05/09/2020 04:49:16.0595] Discovery Request sent to 172.20.201.9, discovery type STATIC_CONFIG(1)
May 9 04:49:16 kernel: [*05/09/2020 04:49:16.0612] Discovery Request sent to 255.255.255.255, discovery type UNKNOWN(0)
May 9 04:49:16 kernel: [*05/09/2020 04:49:16.0619] Discovery Response from 172.20.201.9
May 9 04:49:16 kernel: [*05/09/2020 04:49:16.0705] Discovery Response from 172.20.201.9
May 9 04:49:26 kernel: [*05/09/2020 04:49:26.0000]
May 9 04:49:26 kernel: [*05/09/2020 04:49:26.0000] CAPWAP State: DTLS Setup
May 9 04:50:23 kernel: [*05/09/2020 04:50:23.0133] dtls_disconnect: ERROR shutting down dtls connection ...

[Leo Laohoo]

Factory reset the AP.

[JonRedn11]

@Leo Laohoo in fact, I did it. After that, I connected the AP to WLC but still doesn't adopt it.

[JustTakeTheFirstStep]

The remaining APs that failed to join were also joined.
Since the discovery was repeated with 200.9 and 201.9, it was joined after AP Reset.
Cause not found T_T

[PratishPaul87]

Thanks