Light Disappear After Build

First Sorry for my bad English.

I met a problem just now.

This is a little house. Before building It’s normal.

But ,After I build light.I got this picture:

It seems that the light form the point light is disappeared.
And, Not only this ,but all static point light have this problem.
I tried to delete it and place a new point light But the new one has the same issue.

How can I resolve this problem?

The picture on wall is PaperSprite.
Wall is Built by BSP

if they are static meshes , they will require a second uv channel . here is a method of how to create it .

When you get the lightmap created and imported to ue4 go into the mesh editor and change the lightmap resolution from 32 to 64 or 128. That will get rid of the few artifacts in shadows you’ll get. If they’re still there try 256.

Thank you but the house itself is not static mesh, and picture is not either. Do you notice that the shadow under the bed is also disappeared
Do you have any idea?

try to set the lights to movable and increase the light map resolution until u get a required result . I think it will solve your shadow’s issue . Apologies for late reply

I had try it but it is useless. I increase light map resolution to 256 but noting changed.