2001 Mercedes Benz C200 I keep getting

I think what is happening here is that there is a small switch in the latching mechanism inside the driver door and this switch is no longer functioning telling the computer that the door is open. As for the door locks these locks run off of pneumatics, meaning there is a small pump that produces pressure for small hoses running from this pump to each door latch mechanism to unlock or lock each door. If any of these lines are broken or the mechanisms not longer work will prevent the door from locking or unlocking.
Just to be clear does the remote electronically unlock the all the doors? You said the remote doesn't lock the door and then said the remote opens the door?
Do you plan to diagnose this yourself?

Thanks for the reply. And yes, the remote electronically unlocks all doors including the drivers side which does not close electronically. It also electronically locks all other doors except the drivers door. I hope to diagnose this myself and possibly get to know where the fault is so that I can plan to have it fixed at a garage. Thank you.

Everything you said tells me the issue is the driver door lock actuator. If the vehicle senses the door is open it will not lock the driver door, but the key fob/remote will. My bet is on the door lock actuator assembly.

Thank you very much for your support. I appreciate.