Our WLC running on 8.5.171(recently upgraded) with 1852 AP's every four or five hours my AP's are disconnecting from the controller for unknown reason, Switchport is up, AP uptime is good, so the AP is not rebooting, but AP couldn't able to join the controller. All AP's are in Flexconnect mode with Flex connect local switching enabled.
Controller log: Show AP join stats 00:00:00 shows that
Last AP connection failure: "retransmission to the AP has reached maximum"
last Error occurred: "AP got or has been disconnected"
Last AP disconnect reason: "Unknown failure reason"
or
Last join error summary
- Type of error that occurred last......................... AP got or has been disconnected
- Reason for error that occurred last...................... Timed out while waiting for ECHO repsonse from the AP
- Time at which the last join error occurred...............
AP disconnect details
- Reason for last AP connection failure.................... Timed out while waiting for ECHO repsonse from the AP
Rebooted controller, rebooted all AP's
Have 25 AP's, around 17 AP's are facing this issue per day,
any immediate help will be appreciable
