320d passenger door does not unlock/lock

[Zammy]

My 1st BMW and am loving it, 320d 07 reg. Well all was well until today the passenger front door does not respond to when i press the open button on the fob, all other doors open. It doesn't even work when pressing the central locking button on the dash. Any ideas anyone?

[Mafioso]

Try having a poke around in the locks themselves on the side of the door. May just be stuck and needs lubricating.