In a nutshell. Can you lock it by hand?
If so, then your issue is the actuator or a wire issue (Since there is no noise it is not the normal issue of a defective mounting rivet).
Remove the door panel, check the plug connection. If it is good, unplug it and check it for voltage when you press the lock button.
If you have voltage, then you need a replacement actuator..
No power, then you need to start going backwords and see where you loose the power. Could be a fuse but not likely if the others are working. Could be a relay though as often they are on separate wire banks.