FaceTime fails to connect across my devices. It calls but immediately cancels the call.

I have two iPhones and an iPad all on the same apple ID account. When I try to FaceTime from one of these devices to another it calls and shows a call incoming on the receiving device, but then it immediately cancels the call. I’ve tried many solutions to the issue and nothing seems to work. I have all of them using their own numbers and addresses on FaceTime. I have fixed iMessage to ensure each device is on their own address. I have ensured the dare and time settings are correct. Nothing is working and it used to work.

How can I get FaceTime to actually work on the only devices I will ever really need to FaceTime?