Unity Blender Shadow испортилась

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