Possible cause 1: Your phone is in flight mode.

Solution: Restart the phone in normal mode with full functionality.To view flight board menu options > Settings > scroll to the General tab > Setup Wizard and select an option.

Possible cause 2: Your phone is not receiving any radio signal or the received signal is too weak.

Solution: Contact your service provider and make sure that the network has coverage where you are. If so, search for a network.

Possible cause 3: The SIM card is not working properly.

Solution: Insert your SIM card in another phone. If you still get the same response then contact your service provider.

Possible cause: The phone is not working properly.

Solution: Insert your SIM card in another phone. If this works then it is probably the phone that’s causing the problem. Contact the nearest Sony Ericsson service center.