2003 X5 Door lock

Hi Guys, I have an issue with my 2003 X5 Door lock system. When I lock the doors with the remote key, all the doors will lock. However, when I try to unlock the doors with the remote key the driver side passenger door will not open. I am wondering if this is an issue with the door lock or the actuator. Thanks for your help.

Doesn't unlock even when you press unlock 2x?
Does everything else unlocks except the passenger door? If So it could be the door module but it also could the central module... detailed troubleshooting is necessary which requires electrical equipment and skills...... (starting from testing if Open signal is coming to the door module..etc....)

Does everything else unlocks except the passenger door?

OOps I meant Driver door