Unhappy [Q] Samsung Galaxy S3 installed Omega Rom, not detecting the SIM

I installed this Omega Rom after downloading from omegadroid.co/download-center/ for my S3 I9300, omega version is v58 - XXUGNB6

now everything is working fine except the calling feature, phone is fast as well but when i try to make a call it says not registered on network. which was working fine before, similarly to another S3 I9300 of a friend the same ROM is installed and it works fine without any problem at all. even calling is working fine.

The error message is "Not Registered on Network "

what can i do to recover my phone? can i unroot it ? if so please appreciate any help on how to do it. what could be the issue here if anyone have a idea.

Thanks in advance.