Information Reference
Cisco Aironet Series 2800/3800 Access Point Deployment Guide
https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-3/b_cisco_aironet_series_2800_3800_access_point_deployment_guide.pdf
Reset the CAPWAP Configuration on IOS and ClickOS APs
https://www.cisco.com/c/en/us/support/docs/wireless/aironet-1200-series/99763-reset-lwappconfig-lap.html