iPhone 16 pro max cellular issues

Just upgraded to the iPhone 16 pro max. Since then I’ve been experiencing issues, mostly in the evening, where I can’t make or receive cell phone calls. I have 1 bar during this time. Other features such as texting, FaceTime, using Safari, and playing games all work, just can’t call anyone. Wondering if anyone else is experiencing this or any suggestions.

went to AT&T store and they said it’s an issue with the phone, not the carrier.