GSM shield SIM CARD not recognized

I recently purchased a GSM shield for my project. For the GSM shield i required a SIM card, which i bought from one of the service providers in the area (Virgin Mobile). Once I placed the SIM card into the SIM holder of the GSM shield and tested the connection, the "Network" LED indicator showed that their was SIM card detected or network connectivity.

I am new to using the GSM shield and not sure why this is happening. Is it due to the network provider? a CDMA vs GSM issue? the power supply to the GSM shield? Any help would be appreciated. Thanks.

Don't crosspost. Other topic locked.

The SIM may be locked to Virgin Mobile.

Where can I purchase an unlocked SIM?

I ran into this problem. What shield are you using?

I bought the geetech sim900 and tracphone sim. I replaced both. I got the Arduino official GSM shield, and then I bought a tmobile prepaid sim. It has to be the GSM band.

I think it likely has to do with your sim card. Get a different one that works on the GSM network and has data. Tracphone did not work (blinks rapidly) but then I went to tmobile and did not pair it with a phone and it worked.

If you are in the UK then a Tesco 2g/3g sim works fine in my board; no monthly limits/top ups needed.

You theoretically need a psu capable of 2A but thats generally only for a short time.
For my use, a standard 1A regulator with a 2200uf or greater capacitor seems to be fine.

Any more questions - then mention your make of board.