Same thing happened to me. It was annoying because I arrived late but knew we should be able to get into our room with our Magic Bands. Instead, none of our Magic Bands would work on the elevators nor, as we learned later, our rooms. We ended up searching around the main lobby for someone to help us to no avail. Eventually we found a phone on the wall and had to call over to GCH and wait for someone to come over with a tablet to fix all of our Magic Bands. I thought checking in online would have saved us time by allowing us to go straight to the tower but, in the end, it was a waste of our time.