I've got a problem with my Lightmap. When I build lightning with Lightmass I get these dark spots on my mesh. But as you can see in the images, these dark spots only appear on the shadow side of the building. When the mesh is directly lit by a directional light, the shadows are fine. I also don't understand why those windows are full of these black spots at the edges, because in my lightmap the windows are those 4 rectangles in the upper left corner. I think there is enough space between the different parts in the lightmap.
Can anyone help me to solve this problem?