B777 - Problem with Stairs and Cargo Vehicles

Hello,

When I request stairs and luggage loaders, these don't connect to the aircraft. They come to the a/c, but the stairs don't raise to the dooc level and the loaders don't raise to the cargo doors. This happens only with the 777. I can't ask PMDG because they have dropped their paying P3D customers.

I have searched every where I could think of but found no one with a similar problem. Any help appreciated.

Jean-Pierre Gagné