Unity Blender Shadow en mal estado
This could be a lot of things so keep going down the list until one of them work
1) In Unity import settings enable Generate Lightmap UVs (It's a checkbox)
2) Also Unity Import settings Set Normals to calculate
3) Also Also Unity Import settings Smoothing Angle to 0
4) In blender see if your normals are looking the right direction if not
generate them again
Insert Grepper Name Here