I missed many calls like everyone else. I was not getting calls on any Apple device. I called Apple support and could not fix.
Finally fixed it myself today. WOW is all I can say. It was my Apple Watch causing the issue.
1- Open Apple Watch app on your iPhone
2- Go to Gestures
3- Turn off/disable “Cover to mute”
Done all fixed.
As soon as I disabled “cover to mute” my iPhone, iPad, iMac and Apple Watch started to ring again
As soon as I enable “cover to mute” all Apple devices would NOT ring
So disable “cover to mute” on your Apple Watch and if you need to mute an incoming call just press the crown on the watch
Hope this helps