DTLS session closed for AP, cause: DTLS server session error

[annah1]

Hello , 

I have several APs getting dropped from wlc 9800 ( version : 17.3.6 ) with the error message : DTLS session closed for AP, cause: DTLS server session error

could you please advise what could be the problem 

[Mark Elsen]

  - Have a checkup of the 9800 controller configuration with the CLI command show tech wireless ; feed the output into : https://cway.cisco.com/wireless-config-analyzer/
   Do this first! 

   Further on use these tools for troubleshooting AP join issues  :
                          https://logadvisor.cisco.com/logadvisor/wireless/9800/9800APJoin

 M.
                          

[annah1]

Thank you @Mark Elsen  for your feedback , i tried to upload the file to https://cway.cisco.com/wireless-config-analyzer/ , but i got the same initial page ( see attachement ) .

the file is in txt format .

[Mark Elsen]

  - It should work , remember to use the CLI command show tech wireless ; not simple show tech

 M.

[Rich R]

And think about upgrading to 17.9.4.