Wrapping/Overlapping UV's Error on lighting build

With my static meshes I am getting an Wrapping/Overlapping UV’s Error on lighting build.

These meshes were NOT made in an external package. They were editing BSP’s converted as static meshes, or they came with UE4.

I’ve tried to research this but found nothing super useful. Any ideas?

When you export/convert a BSPc brush into a static mesh, the mesh is not unwrapped.
All mesh faces cover the entire UV space, thus they overlap.
You need to open the exported mesh in an external 3D application and properly unwrap the geometry.