Cause 3 of 3: Mobile data is turned off
To use the phone's internet connection, mobile data needs to be turned on.
Solution: Turn on mobile data.
1 Find "Data usage"
Slide two fingers downwards starting from the top the screen.
Press the settings icon.
Press Data usage.
2 Turn mobile data on or off
Press the indicator next to "Mobile data" to turn the function on or off.
3 Return to the home screen
Press the Home key to return to the home screen.