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How do I solve this problem, when I load a building from Blander to UNREAL ENGINE4 it becomes black or shade on the roof of the building

did youcheck the normals in Blender before exporting?

Yes

not sure where the issue is. Could you show a screenshot of the export aettings you use in Blender?

check lightmaps. it could be:
-Lightmap UV not assigned to the correct channel
or
-Badly made lightmap UV’s (not using the space well, overlapping, outside 0-1 space, etc)
or
-lightmap resolution too low