It happened to me as well. Out of the blue. I was able to stop the audible alarm by rebooting. After this, FSD was working again even with the red steering wheel caution on the screen. Once i got back in the car after a few hours at work, all was normal again.
I fixed mine with electrical tape. My doors could be pushed in a bit from the outside. So I first tried to adjust the striker inward but it was at the limit already.
I added a few loops of tape and this fixed a B pillar rattle I had and the Door/mirror vibration.
(picture is not my door)