Hello @BoboXX 

You can click "Association Timeout", and put the mouse pointer on the circle on the right side, it will show you a list of devices that generated this error. The same as errors "Blocked by Access Control" and "WPA Authentication Timeout/Failure".

  @KyrieM 

It's the MAC address of one of my AP.

  @BoboXX Because your devices are named after their MAC addresses, the names displayed will be changed too if you change your devices' names.