Can someone PLEASE tell me how to fix this? It’s a mesh I converted from BSP.
Take a look at this thread: https://answers.unrealengine/questions/69683/erorr-object-has-wrapping-uvs.html 
"It means that the specified light map coordinate has overlapping UVs. You can try fixing it by opening your static mesh in the viewer and using the auto UV tool. It should create the new UVs in channel 1 by default but you will have to change the lightmapcoordinateindex setting to match. "
More information about lightmaps: ://
This guide on the Wiki for Lighting Troubleshooting and Tips should help as well: https://wiki.unrealengine/LightingTroubleshootingGuide
This is a guide that Eric and I have setup to help with more common lighting issues.