Lightbuilding-result is strange

Hi everybody,
i am quite new to Unreal and trying myself with an architectural visualisation.
…And i am facing already a Problem i can’t understand:
i’ve put all my static meshes into a blueprint and set all objects to static.
there is just the sunlight emmiting, which is set to stationary.
the result is, that i am in general getting shadows, though some of the objects seem to not cast any shadows at all, leaving a disturbing result.
(In the Picture you see the ceiling casting a shadow, the right wall is not)
What do you think?

thanks and have a good sunday


I would say that your lightmap resolutions are low…

Make sure your wall has some surface facing outwards, you can try making the wall double sided or make some simple geometry on the outside to block the incoming light.