Cause 8 of 12: Flight mode is turned on
When flight mode is turned on, all wireless connections on the phone are turned off, including the connection to the mobile network.
Solution: Turn off flight mode.
1 Turn flight mode on or off
Slide two fingers downwards starting from the top the screen.
Press Airplane mode to turn the function on or off.
2 Return to the home screen
Press the Home key to return to the home screen.