I have a IAP-224 ROW AP that I am having the same problem also. I know they work in US because I have 4-5 identical ones deployed across our campus and have been in use for years. We got shipped the wrong order when they first came out and support just had us convert them to campus-AP's and all has been good. Until I did a purge_env to reset it and redeploy and it wiped the country code. I then did a factory reset and converted the AP back to campus-ap, but US is not listed in the country code list so it will not accept the change and leaves me with an "E" flag on the controller. I also upgraded to latest firmware but US is still not listed. I've tried setting country code in CLI and also on the GUI.
Anybody have any different ideas on this?