Is it possible for you to try this SIM card in another phone to rule out it's the phone itself?
The Sim card works fine in my old phone
So it sounds like a phone issue… could the SIM tray be a little loose perhaps? Is it still under warranty?
I would hope it's still under warranty. I just got it and the tray fits snug and slides in smoothly. Should I do a network reset?
May as well attempt a network reset. It’s one of the first things to attempt after swapping sims around. If it’s still being problematic, then I’d exchange the phone while you still can.