Why does the ringtone not play on incoming calls on FaceTime?

[iMore Question]

When incoming FaceTime calls are called no ringtone sounds to alert that incoming call is being placed

 

[Rob Phillips]

Welcome to iMore! Are you getting a vibrating alert and a visual alert on the screen that you're getting a call? Check a few things:

1. Make sure your phone isn't on silent using the silent/mute switch on the left side.
2. Turn the ringer volume up by unlocking your phone and using the volume up button (located just below the silent/mute switch).
3. Make sure that you don't have Do Not Disturb turned on. If it's on you'll see a little crescent moon icon at the top of the screen near the battery indicator. You can switch DND on in the Control Center.