Favourite contacts still don't ring through on Do Not Disturb (DND) mode

Hi. I have DND set up on my phone and my wife and daughter's (who is diabetic) phone numbers starred as favourites in Samsung's contacts app. I also have the DND settings set to allow Favourite contacts to ring through. When my wife calls me, however, it doesn't ring at all (zero sound). Does anybody have any suggestions?

Look at this photo. Look at the Ring volume slider. Make sure you move it all the way to the right. Also - you can slide the Media to the right. One last thing - Press the volume slider on the side of your phone. Move the slider up. Also look at the very top of the slider. There should be a bell there. Make sure there is not a / slash through it. If so press the bell to turn the volume back on. ( Check these settings when DND is turned on to make sure it is working properly.) Have some one from another phone that is favorite contact call your phone and see if it rings. Good luck!

In addition to those check points mentioned by @jameny5 , go to the contacts app, tap your wife's name as well as your daughter's name, check their ringtone options. Make sure that they are neither 'None' nor 'Silent'.