I have a problem with iMessage and FaceTime
I can't link my phone number to iMessage and FaceTime, an activation failure pops up
iPhone XS, iOS 14
You need to change/add the number on your Apple ID. After the change, allow up to 24 hours for the change to sync. Before trying to make the change, sign out of Messages/FaceTime on all devices/computers.
Messages - If you get an error when trying to activate iMessage or FaceTime.