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 three 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 into 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. Hey everyone and happy new year:
    i have an issue concerning the wireless. It is quite interesting. I have an Wlc aireos and all devices are connecting to it. When i migrate the AP to a new wlc catalyst 9800 , only few devices are not connected. All are the same prototype they are robot but the one who are not connected are old prototype. I did a wireshark capture and i see all the frames going through but in the 4 way handshake only M1 is send from the AP and no answer form the device. I see a disassociation with a reason 4way handshake timeout. In the wlc AI

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  4. Hello Mina

    Take a look at this lesson that has to do with troubleshooting APs not joining:

    Now having said that, can you give us a little more information about what model APs are not joining and which ones are? I’m assuming that this has to do with a compatibility issue. Check to see what APs are compatible with the 9800 and which older ones are no longer supported.

    I hope this has been helpful!


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