Sim card invalid after 5 minutes

Hi, I just bought a samsung A50, I set it up with my carrier over the phone. The sim card works after restarting the phone, but exactly 4 minutes and 30 seconds (I timed it), it times out and displays “invalid sim card" and asks to enter a PUK number. However, the PUK number that came with my sim card, does not work. The PUK number was given to me by my carrier, as it was listed on my account.

Ultimately, I just want to know why my phone reads my sim card, then stops after about 5 minutes. It works every time I restart it. I have yet to look at the sim card reader by taking the phone apart. I'm afraid that I'll break it or make it worse. Any pointers or alternate options?

Edited to add: I am able to make a phone call and continue the phone call even after the sim card stops being read. It timed out and displayed invalid, but while I am in a phone call, I am able to use my data, texts and voice. Once I hang up, it goes back to no service and I have to restart my phone.