FortiAP 221E Web UI and Setup Issues

I have a FortiAP 221E that is connected to a FortiSwitch (108D-POE), and all of this is behind a PFSense firewall (no FortiGate/FortiWifi).  I can connect to the web login page on the FortiAP, and can authenticate with the default credentials (admin, no pwd), but then the main page just flashes up, then it goes back to the login page.

I can SSH into the unit and make some setting changes via CLI (I changed address mode to static, set an IP, Netmask, etc).  But I can't figure out how to actually enable the AP so it works.  

Have tried doing a reset (cfg -x) back to factory default's a couple of times, but the same thing happens above.

Any advice on getting the web UI to work?  Or any advice/tips on navigating the CLI?  I found the CLI reference for FortiAP here (https://help.fortinet.com/fos50hlp/54/Content/FortiOS/fortigate-wireless-54/reference.htm), but it's not much help.