Default Just one SIM will not work with my phone

Hello everyone, i have a Galaxy S3 with cyanogenmod 10.1 installed. This morning my cellphone started to give me no signal, I initially though it might be some problem with my carrier, but clearly this is not the case. I tried to swap SIM cards with my mom cellphone (another S3 with ROM stock), and the two SIM worked. I put again the two SIMs in the respective phone, and my phone still couldn't get signal with MY SIM, while with my mother's there weren't any problem

Basically: my phone can't read MY SIM out of the blue, but my SIM works with other phones. And my phone aswell works with other SIM. This seems to me without any sense. Can someone figured out why it does this?
I tried to wipe the phone, change rom (from cyano 10.1 to 10.2), the issue is still there.