Does it buzz or make any sound when you press the buttons? Probably a faulty actuator or connector if not. Remove the drivers interior door panel to diagnose.
It could be a broken wire either in the door itself or the wiring bundle that runs to the door. In my case I had a similar problem and it turned out to be a broken wire at the actuator in the driver's door. Relatively easy fix, just very limited space to work on it..
I had a similar problem, only drivers door would not lock, sure enough I unplugged the connector in the door hinge, pulled back the boot and had a broken wire, fixed it, and all was well again.
I just recently had a problem with my drivers door lock. I had to manually press down the lock button for it to lock the door. Thinking it was the actuator, I went out and purchased one. Found out from my mechanic that it was just not the actuator, but also the wiring in the door. Both were fixed and now lock works fine.