AP can not join WLC4402 : Max retransmission count reached!

Unanswered Question
Oct 14th, 2009


I have WLC 4402 soft with AP 1242g

If I diconnect the ethernet cable of an an AP form 5 minute, and then reconnect it, the AP could not join anymore.

The message every one minute on the AP is:

*Oct 14 07:36:55.067: %CAPWAP-3-ERRORLOG: Go join a capwap controller

*Oct 14 07:36:55.000: %CAPWAP-5-DTLSREQSEND: DTLS connection request sent peer_ip: peer_port: 5246

*Oct 14 07:37:09.000: DTLS_CLIENT_ERROR: ../dtls/dtls_connection_db.c:2013 Max retransmission count reached!

The only way to overcome this pb is to reload the AP.

Have you got an idea ?

Michel Misonne

I have this problem too.
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mmisonne Thu, 10/15/2009 - 01:42


Thanks for this information.

In the meantime, I downgrade from 5.2.193 to 5.1.163 , and I get rid of this problem.

Michel misonne

weterry Thu, 10/15/2009 - 19:14

From the log you provided, the ap obviously had IP connectivity since it discovered the controller. The error isn't at the JOIN though, it is at the DTLS setup (5.2/6.0), so 5.1 wouldn't be doing this as far as I know.

Bottom line is that it looks like your AP was not able to establish a secure connection to the controller.... I suppose there could be many causes for this, but nothing specific jumps to mind to look for.

Georgios Nikitas Thu, 11/05/2009 - 03:10

The same problem here:

WLC 4402 with v.6 image

APs: 1252, 1140

Error message:

DTLS_CLIENT_ERROR: ../dtls/dtls_connection_db.c:2013 Max retransmission count reached!

%DTLS-3-HANDSHAKE_RETRANSMIT: Max retransmit count for is reached.

I haven't found any solution yet but the problem happens very often. I thought that it would be documented by Cisco but I couldn't find anything about it

engineerangelo Thu, 03/11/2010 - 22:48


I have the same problem. I have 2 WLCs both 2106 running v6.0.188.0. I'm setting up H-REAP on both of them. I have 2 1242AG LAPs and both of them have no problem registering, but my 1130AG LAPs cannot register. The error on the 1130AG is DTLS max retransmission reached. I don't know why the 1130 can't register while the 1242 doesn't have any problem. Additional info, I don't have any problems registering the LAPs in Local Mode.

engineerangelo Tue, 03/16/2010 - 21:44

My problem is solved. Apparently when we left, we turned off the WLC and the LAPs, then the next day, when we turned them on, the LAPs automatically registered.

engineerangelo Tue, 11/15/2011 - 18:11


I recently encountered this problem again. But this time, I am using version And this time, the APs are arleady registered and running for some time now. Until one day some of the APs began to disappear from the WLC. Logs from the APs that suddenly disappeared from the WLC are ordinary DTLS logs:  DLTS client error, maximum retransmission reached, etc. We really didn't know what went wrong, we just reset the APs and the switches. We didn't do anything to the controller. Has someone experienced this before? Please help. I want to prevent this from happening again but I don't know the cause of the problem.

Thanks in advance.

Scott Fella Tue, 11/15/2011 - 19:55

Do you have a second WLC you can move the AP's to? The reason I ask is because if this happened to me and after a while something like this would happen, I would reload the code and build the wlc from scratch. That is what I would do.

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