Do Not Disturb - Not working

When I enable DND, it still doesnt ring for incoming calls.
I have it set for favourites only, and when my favourite contacts call, my phone still wont ring.
I have my volume bar up, and my phone is on silent.
What could I be doing wrong?

My DND settings are:

Manual: OFF

Scheduled: OFF

Allow Calls From: Favourites

Repeated Calls: ON

Silence: Only while iPhone is locked