Webserver on the controller would maintain the webui and captive portal features. When the webui got locked up by uploading wrong certificates, a restart on the process would help to recover
Command to restart:
#process restart httpd
Using the above command we can restart any process and the list will be available in show process monitor statistics.
Note: restarting fpcli process would reboot the controller. Restarting auth or ipsec would break the tunnel established to Raps.