1142 AP can't join the WLC - hardware failure

For those who may encounter something similar to save troubleshooting time.

What you may observer:
APs went offline and couldn't join the WLC anymore. It also couldn't join another WLC running on a higher code version.

AP model: AIR-LAP1142N-E-K9


Errors you will see on the WLC (Monitor->AP join)
8.0.121.0  Ignoring config status as mac address is not present in database
8.1.131.0  Invalid License in configuration request

View from AP CLI:


APe05f.bXXX.XXXX#
*Mar 29 11:47:12.944: %DTLS-5-SEND_ALERT: Send FATAL : Close notify Alert to 192.168.88.99:5246
*Mar 29 11:47:23.000: %CAPWAP-5-DTLSREQSEND: DTLS connection request sent peer_ip: 192.168.88.99 peer_port: 5246
*Mar 29 11:47:23.743: %CAPWAP-5-DTLSREQSUCC: DTLS connection created sucessfully peer_ip: 192.168.88.99 peer_port: 5246
*Mar 29 11:47:23.744: %CAPWAP-5-SENDJOIN: sending Join Request to 192.168.88.99

Radio interfaces cannot be detected even after AP re-image:

APe05f.b915.d0c2#sh int desc
Interface                      Status         Protocol Description
BV1                            up             up
Gi0                            up             up

Resolution: hardware failure.