Ap can't join WLC 5508 Max retransmission count reached for Connection 0x64FF59A0!

[kettepong]

I have environment wlc 5508 and ap 702w 250 units config flex-connect mode

WLC Firmware 8.3.102.0

WLC IP:172.18.210.1

WLC and AP connect same site 

wlc and ap same ip subnet and wlc enable dhcp for ap Work!!

I found problem many ap randoms disassociated from controller and i console ap show this error

*Nov 3 03:58:39.000: %CAPWAP-5-DTLSREQSEND: DTLS connection request sent peer_ip: 172.18.210.1 peer_port: 5246
*Nov 3 03:59:08.999: DTLS_CLIENT_ERROR: ../capwap/base_capwap/dtls/base_capwap_dtls_connection_db.c:2214 Max retransmission count reached for Connection 0x64FF59A0!

*Nov 3 03:59:38.999: %DTLS-5-SEND_ALERT: Send FATAL : Close notify Alert to 172.18.210.1:5246
*Nov 3 03:59:38.999: AP has SHA2 MIC certificate - Using SHA2 MIC certificate for DTLS.

 **Solution for today i tried reboot controller after that ap can join to controller and 1-2 day after reboot controller many ap randoms disassociated again

Please help me solve

Thank you very much

[Rasika Nayanajith]

Unless you really needs features added on 8.3.x code, I would suggest you to try 8.2.130.0 code instead & see the stability

See below thread for any known issues that's going to be addressed in upcoming 8.3 MR1 maintenance release

https://supportforums.cisco.com/discussion/13136886/83mr1-beta-availability

HTH

Rasika

[kettepong]

Dear K.Rasika Nayanajith

i suspect about lan cable because some ap disassociated from controller and associated many time i tried change lan cable it work not disassociated from controller. 

[kettepong]

Dear K.Rasika Nayanajith

I have more information about Max retransmission count reached for Connection please see picture if ap not join to controller it can't ping to WLC but can access via telnet. (Left of the picture is ap join to controller can ping and right ap not join can't ping.)

BTW. i will downgrade firmware 8.3 to 8.2.130 by you recommend and tel you again.

Thank you very much.

[kettepong]

Dear K.Rasika Nayanajith

i downgrade firmware 8.3 to 8.2.130 by you recommend and still problem please help me find a solution