Current status - Denied We can’t unlock your device because it’s no longer active on an AT&T account.

I tried to unlock my iPhone I used to use while I was on AT&T through the official AT&T unlock page, but it was denied.

I believe this phone satisfied the unlock requirement and I properly chose [NO] for [Do you have a mobile number from AT&T?] option and entered correct the phone's IMEI #, I still getting the below status update.

I tried multiple times , but I got same results.