You have installed a LEAN image on the AP.
The LEAN image does not include a GUI to save space for other tasks such as storing Captive Portal pages.
The idea is as you are controlling the AP remotely, there is no requirement to have a local GUI.
if you require a Gui you can use the CLI command on the controller to load a new version of the AP7502 code
If you look at the ZIP file you will see both images
AP7502-LEAN-5.9.2.1-002R.img
AP7502--5.9.2.1-002R.img
if you use
device-upgrade command
device-upgrade load-image ap7502
URL Location of firmware image
URLs: tftp://[:port]/path/file
ftp://:@[:port]/path/file
sftp://:@[:port]>/path/file
http://[:port]/path/file
cf:/path/file
usb:/path/file
IPv6 URLs: tftp://[:port]/path/file
ftp:>@
sftp://:@[:port]>/path/file
http://[:port]/path/file
on On AP/Controller or RF-Domain
or you can simply use the controller to control the AP as intended.
Please note all new version of controller code should install the LEAN image of the access point code for the above reason
This is different from the LEAN image of the controller which means that it does not include the AP images.