The message indicates that the Access Point (AP) attempted to poll the client a certain number of times, but did not receive a response. Therefore, the client is removed from the association table.
This issue is commonly seen when the client and AP are attempting to communicate in a noisy Radio Frequency (RF) environment.To resolve this issue, see if a snapshot reveals noise in the radio spectrum by trying to run a carrier busy test on the AP. Attempt to alleviate any unwanted noise.
If using non-Cisco clients, try disabling Aironet extensions on the AP radio.
Perform these steps:
Select Network Interfaces.
Select the Settings tab at the top of the page.
Scroll down to Aironet Extensions and set to Disable.
Apply the new settings.
If the problem persists, make certain your clients are running their latest firmware or drivers.
If the problem continues to persist, contact your nearest Cisco Support Center.