Missing Contac Shadows in Scene

Got some problems with missing shadows between my objects. As an example i got a screenshot here.

44784b5242bbbc4c6d23449d5a431e4d7ba7d117.jpeg

As you can see between the desk and the headphone or that file basket is no shadow.

For lights in the scene is used the LightStage from the Advanced Lighting Scene and some spotlight lamps from the ceiling.
Tried to tweak ambient occlusion in the post process volume, but without success.
Also tried the contact shadow option in the spotlights, but i always get a bad result.

Hope you can help me with that, really like to finish the project :slight_smile: