Cisco WLC Debug AP not joining

Sometimes you have an AP that for whatever reason doesn’t want to join the WLC. To solve this, there are 3 things you could check:

  • The WLC logfile (management > logs).
  • The console of the access point.
  • The console of the WLC.

You don’t always see what you need on the access point console or the wireless controller logfile, the best way to solve these issues is to enable a debug:

(Cisco Controller) >Debug capwap errors enable

This will output the following items:

(Cisco Controller) >show debug

MAC debugging .............................. disabled
Debug Flags Enabled:
  capwap error enabled.
  capwap critical enabled.
  lwapp errors enabled.

Once you connect the AP it will join the WLC and you’ll see the following debug:

(Cisco Controller) >*spamApTask3: Feb 05 09:19:22.696: 00:22:90:92:c2:80 Failed to parse CAPWAP packet from

*spamApTask2: Feb 05 09:20:58.000: 00:22:90:92:c2:80 Refusing Discovery Request from AP 00:22:90:92:c2:80 - limit  for maximum APs supported 5 reached 

*spamApTask2: Feb 05 09:20:58.000: 00:22:90:92:c2:80 State machine handler: Failed to process  msg type = 1 state = 0 from

In this example the debug message is pretty clear…we hit the license limit of the WLC. Whatever the reason, this debug will produce a useful message that gives you more insight what to look for.

To disable all debugging:

(Cisco Controller) >debug disable-all 

Hopefully this is helpful to you to debug some of your troublesome access points!


Forum Replies

  1. Hi Rene,
    I have an issue with an AP not joining the WLC, I have 3 AP’s on the WLC, one of them keeps drop the connection, when I check it by show cdp nei deta it has the correct IP address and it’s up on the switch, I can bring it back up by bouncing the port but it will come up for less than 3 minutes or so, please check the debug below on the WLC.
    Note: the IP address and MAC address is hidden for privacy purposes.
    Thanks in advance

    Cisco Controller) >*spamReceiveTask: Jul 26 15:25:07.135: XX:XX:XX:XX:XX:XX Msg Timeout for, max retries: 5 (C

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  2. Hello Wisam

    The first thing to do is to determine if the problem is in your network infrastructure or your AP. Try swapping the malfunctioning AP with one that is functioning correctly and see if you have similar behaviour.

    If the same AP malfunctions again, then the problem is with the AP. If the new AP malfunctions, then the problem is the infrastructure.

    Secondly, once you find out where the problem is, there are several things you can do:

    If the problem is the AP, try bringing it up to the latest stable firmware version as some bugs have been found with s

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  3. Hello,
    i am so sorry i did not explain well the situation. I have 2 controllers an old one wlcAIREOS and a new one catalyst 9800. The migration of the access point goes well, no problem for that.
    I have some AGV it is automated guided vehicule who can not connect to the access point. In the capture i only see 1 M1 from the access point but no reply from the agv. So i can not not migrate those Access point to the new controller. But those agv works like before in the old wlc. The funny thing is there is others AGV a lot of them are connected well to the catalys

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  4. Hello,
    yes, you are right. I should do another capture in the old WLC and compare it with what I did with the capture with the catalyst. Most of the capture with sniffer mode, i see 4 way handshake timeout.
    I will keep you update :slight_smile: Thanks again so much Mr Lazaros.

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