broken shadows after building light

Development Rendering
1

I am getting incorrect shadow after I build lighting.
the first picture is inside the mesh editor where everything looks ok. But in the main editor if I build light, then the shadows do not work properly. Any ideas about how to fix it?
All settings are default at this moment, I just imported the mesh as an obj in a default scene.

https://live.staticflickr.com/65535/49750821412_0e2069b064_b.jpg

https://live.staticflickr.com/65535/49749954408_a6a2e9aac8_b.jpg

2

You shouldn’t have that all as one mesh

Part of the issue is that the lightmap resolution is too low.