FACETIME "CALL FAILED" EVERY TIME WHEN CONNECTING

My facetime was working fine - then suddenly from one day to the next stopped working. Any time I try to make a facetime call or receive one, when either party hits "accept" it immediately disconnects and says "call failed." I've tried updating to the latest iOS (14.3), toggling FaceTime on/off with and without a phone reboot, and renewing all of my network settings. Please help???