I want to share more about my frustrations with this issue. I have iPhone 11 Pro and the issue occurred immediately after I updated my phone to iOS 14.7. 1.
Here are my trouble shooting journey:
1) With carrier: changed sims card twice, reset network settings, verified there are no blocks on my account. Visited 2 stores and 2 phone calls with support.
2) Apple support: Reset all settings, Reset network setting, Erase all content and setting (4 times: reset with backup, reset with laptop iTunes with backup, reset with laptop iTunes with no backup, reset with no backup). After numerous long calls with apple support, I was told to go back to my carrier to verify or wait for iOS 14.8.
After I updated to iOS 14.8, still no service and went to apple store hoping to get some help:
3) Apple Genius Bar: ran diagnostics report and found no hardware issue. I was told that my phone ran out of warranty and needs to pay to get it replace or get a new phone.
It have been a month with no service and I am still paying my carrier. This is a very frustrating situation. User did nothing wrong but ended up having pay to get the issues fix. It’s not even 2 years yet with my iPhone 11 Pro!!