Is it possible that SIM pins were damaged by an adapter? Several people have reported that kind of problem on the forum. Another possibility would be the SIM card not making good contact. I had that problem intermittently and solved it by installing a thin plastic shim cut from a milk bottle between the SIM and metal cage of the socket (barely visible in photo).
![[Image: AmvV4M7r_o.jpg]](https://images2.imgbox.com/3a/7c/AmvV4M7r_o.jpg)