Overlapping uv/invalid lightmap settings

So I downloaded a free model from blendswap and opened in blender. Exported it as fbx and imported in UE4.
But when I build light I get the error :“Overlapping uv’s”. So I found this tutorial: A new, community-hosted Unreal Engine Wiki - Announcements - Unreal Engine Forums

I did it a few times, but didn’t work either.

I looked up a lot of Solutions but none helped.

Help is really appreciated !

It means that the model has such horrible uv maps, not even the auto generator can handle it.

try watching this: Lightmap Creation for Unreal Engine 4 - YouTube