Cisco WLC Debug AP not joining

This topic is to discuss the following lesson:

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 (Cisco Controller) >*spamReceiveTask: Jul 26 15:28:18.559: XX:XX:XX:XX:XX:XX Echo Timer Expiry: Missing Echo from AP XX:XX:XX:XX:XX:XX, Closing dtls Connection. *spamReceiveTask: Jul 26 15:28:18.560: XX:XX:XX:XX:XX:XX Incorrect message is being sent to AP :10:10:10:10 (XXXXX) by Controller: !@.12.12.12 (XXXX) Not posting onto message queue *spamReceiveTask: Jul 26 15:28:18.560: XX:XX:XX:XX:XX:XX Unable to delete all station message to *spamReceiveTask: Jul 26 15:29:28.624: YY:YY:YY:YY:YY:YY DTLS connection was closed

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 several older versions.

If the problem is with the network, check the following:

  1. Check STP that convergence is taking place and that it is stable
  2. check to see that there is no power or cable issue. Take a look at this Cisco support forms thread for more details.
  3. Try changing the port of the switch that you are using. It could always be a bad port…

Try these out and let us know your results so we can see if we can help you further.

I hope this helps!


Looking at this output, it seems a connectivity issue between the WLC and AP.

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 AIREOS it works. I don’t know what to do. If some had this issue. Thanks again :slight_smile:

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!


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 catalyst 9800. Only few of them who are the same model can not connect. Thanks again and take care.

Hello Mina

Wow, that’s an interesting problem. So the same APs on the old WLC will allow those AGVs to connect successfully, but those same APs connected to the new WLC will not allow some AGVs to connect. You will have to take a look at the details of how the AGVs connect, and what parameters they use to connect. Look at their documentation and see what standards are used for their wireless connections, and compare them to the standards used by the newer AGVs that can connect. There must be a specific parameters that’s not allowing connectivity.

You may need to take a look at what the new WLC does differently compared to the old one. What security and encryption is being used, what authentication methods are supported, and take a look at the PSK authentication process as well.

Troubleshooting this kind of issue can be challenging, but keep us posted on how you get along…

I hope this has been helpful!


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.

1 Like

i just wanted to keep you updated, there were a privacy bit missing. The endpoint devices did not like what the Access point send and then the endpoint send a dissassociation. Cisco fixed the bug by upgrading the wlc controller.

Hello Mina

Ah, that’s great, thanks so much for keeping us up to date, it is much appreciated. This way we can all benefit from your experience.

Thanks again!!