Central locking with defects

Hello,

When I open the car with the key in the driver's door, the passenger door doesn't open properly. When I open the driver's door, the passenger door opens and then jumps back down a few millimeters. I have to hold the key in the same position until the central locking system has finished unlocking, then the driver's door can also be opened.

Does anyone know about this problem? What can I do?

Greetings

manx