Hello @StavrosK
This is the only online MSM AP CLI guide I could find. It is for a bit later version but probably most of the commands are the same
https://support.hpe.com/hpesc/public/docDisplay?docId=c04917086&docLocale=en_US
as far as I remember the MSM APs or controllers didn't have any AAA test tool like the Aruba controllers have. I also cannot see such an option in the CLI guide.
If you cannot connect wireless clients to an SSID which enforces 802.1x authentication, maybe the only option to test RADIUS communication would be to enable RADIUS authentication for admin users. Then you can try to connect via SSH or HTTPs to the management interface of the AP using an account which is not locally defined but authenticated via RADIUS. If this is working then it should mean that RADIUS communication with the remote RADIUS is working.
Of course you should make sure to not disable local authentication otherwise you can lockout yourself from the AP if the remote authentication is not working.
I think this should be these commands
admin radius authentication
admin radius authentication server <name>
And make sure that this line is not removed.
admin local authentication
As it was already mentioned the MSM product line is end of support.
BTW don't you have https access to the AP? The webUI is more intuitive for configuration. Or do you have TLS issues when trying to access the webUI?
I remember some older versions were using SSLv3 and the connection was not possible.