We had the same problem on both of our new sciphones. After long hours of research we finally found an easy solution to it so hope this helps.
1) Shut down your phone completely (you will know because a red sign will come up on your phone and you have to confirm that you are shutting it down).
2) Take our your battery and then your sim card
3) Make sure that your sim card is in the right way. (It has to be on the highest slot, not the one closest to the bottomof the phone, and the metal plates have to be facing down, or towards the phone).
4) Reinsert your battery and then start your phone up again
5) Go to restore factory settings and plug in the code 1122 when it asks for one. NOTE: Your phone will reboot, and when it turns on it should be okay.
We tried everything and this is the only thing that worked. We had t-mobile sim cards for both phones and it worked fine. Good luck!
-twins-