Hello everyone!

Whenever I turn off my phone, and turn it back on, a message appears, something like "Insert SIM card". The SIM card is properly inserted, though. The only way I found to fix this problem is to take the battery out, then put it back in, but I've recently acquired an Otterbox, and going through three protective layers is becoming really annoying.

Can anyone tell me why my phone doesn't recognize the SIM card after it is turned off and on again, and how to fix this problem?

Thank you in advance.

Your SIM card might be going bad. Stop into a local T-Mobile store and they should be able to swap your SIM card at no charge.