As 2 are working I would doubt it's a fuse, but depends if all 3 are on the same circuit.
So 1st check all fuses & the RCD's are all OK.
If they are OK, could be a simple (but still potentially dangerous)as a connection come adrift at either the RCD or socket. Otherwise, it could be the cable has chaffed on some furniture along it's route. (again potentially dangerous.
Unless familiar with electrics, IMHO get your Dealer (if under warranty) or a qualified Electrician to test it out.