- Make sure that your phone is on and that there is sufficient signal strength. To increase your phone's signal strength, try moving your phone slightly, or move towards a window if you are calling from inside a building.
- Make sure that your phone is not in silent mode: Press a volume key to see the volume status bar at the top of the screen, and tap the ringing mode icon.
- Check the ringing volume.
- Make sure that call forwarding is not switched on: Tap the phone icon > ... > Settings.
If the problem persists, restart your phone by pressing and holding the Power and Volume Down keys simultaneously until the phone vibrates. Release and the phone will restart.