If the "your phone is not registered on a network" error has popped up on your Android phone, you know how frustrating it can be. Whether you want to call your family ...

Use a SIM ejector tool or paperclip to gently remove the SIM tray. Take out the SIM card and inspect it for damage, such as ...

Getting an invalid SIM on iPhone and don’t know what to do? Let me help you with some solutions that should fix the problem. Check out the details as you read further on this post. How would you feel ...

Some owners of Apple's new iPhone 4S have been hit with SIM card error messages, even if they are connected to a CDMA carrier that does not use SIM cards. One reader ...

Sareena was a senior editor for CNET covering the mobile beat, including device reviews. She is a seasoned multimedia journalist with more than a decade's worth of experience producing stories for ...