Default [Q] sim card

My nexus 5 will not read any sim card at the moment. I flashed back to stock 4.4.3 and ever since that, no matter what carrier sim card I put in, I get no call reception. The phone is recognizing there is a sim in because I flashed a custom ROM and whenever I put in a sim from T-Mobile,att, etc., there APN settings come up. I have no idea what's going on. I am no noob. Any suggestions would be greatly appreciated.

Sent from my SAMSUNG-SGH-T989 using XDA Free mobile app