My phone is unlocked so why won't a new SIM card work?

[charchar81]

I just bought a new unlock gsm phone. xgody x500. I bought a new ptel sim card. I activated the sim. The phone keeps saying no sim card installed and won't let me use my service. But i was sitting in my car at a gas station and i my service started to work. Then it went back to the sim card not installed. I tried installing all kinds of apn apps. None worked. Kept saying not allowed 3rd party apps to write apn settings. i tried rooting my phone that did'nt work. Can anyone please help me.

 

[Rukbat]

Either The SIM card is intermittent, or the SIM card port in the phone is.

(The APN is only used for mobile data, not to connect to the network. And rooting has nothing to do with the SIM.)