楼主可以参考一下下面的文档
Troubleshoot a Lightweight Access Point Not Joining a Wireless LAN Controller
https://www.cisco.com/c/en/us/support/docs/wireless/5500-series-wireless-controllers/119286-lap-notjoin-wlc-tshoot.htmlLAP Does Not Join the Controller, Why?
Check the Basics First
Can the AP and the WLC communicate?
Make sure the AP is getting an address from DHCP (check the DHCP server leases for the AP's MAC address).
Try pinging the AP from the controller.
Check if the STP configuration on the switch is done right so that packets to the VLANs are not blocked.
If pings are successful, ensure the AP has at least one method by which to discovery at least a single WLC Console or telnet/ssh into the controller to run debugs.
Each time the AP reboots, it initiates the WLC discovery sequence and tries to locate the AP. Reboot the AP and check if it joins the WLC.
"AP fails to join controller" - LAP fails to join Wireless LAN controller (WLC)
https://community.cisco.com/t5/wireless-mobility-documents/quot-ap-fails-to-join-controller-quot-lap-fails-to-join-wireless/ta-p/3129919Re: 2602i does not join 1852i / mobility express
https://community.cisco.com/t5/wireless-and-mobility/2602i-does-not-join-1852i-mobility-express/m-p/3723418#M103823
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Rockyw | If it solves your problem, please mark as answer. Thanks !