The model how it looks in unity:
And here is how it looks in blender:
Can anyone help explain why it isn’t working?
I believe blender shoes the back side of faces, while unity doesn’t. Just make sure that the face is facing up not down.
Ho do I do that?
Just try remodeling that surface with a cube. Make sure that that facing the correct way.
May be worth mentioning that I am slightly new to blender
Fixed, I just selected the faces and did “Flip Normals”
I only know the basics of blender myself. However I have run into this problem a few times and it can be annoying. 