Errors in building lighting for HTML5

I’m making an architectural scene, and I keep running in to lighting errors. Seem to have to rebuild every time. I don’t know how to fix them, it’s frustrating me.
I run in to a couple of errors. Seems are still visible. Some noise on the walls and bleeding shadow and bleeding light aroud edges.
I modelled the building using blender. Exported to UE4. I used UE4 to generate lightmaps.

How can I fix this?
Thnx, Lexa