You can mechanically lock the door from outside with the key by turning it 90 degree. It might need a mild force.
I can suggest basic things to check, further investigation needs an oscilloscope.
First thing is the fuse 29 at the glove box (and maybe 27).
The drivers door module has 3 connectors. Pin 1 on the 5-pin connector is the voltage supply and pin 2 is the ground. The P-BUS line should have 12 Volts (if no one is using the line) which is the 11th pin on the 18-pin connector. These are the very minimum requirements for the module to work (after locking and unlocking the car).