Sun shines through walls after I built lighting...

How do I get my preview shadows back? Screenshot really show be showing me standing in shadow but I’m behind a wall but in sunlight…

I think the problem come from the UV map from your mesh. Can you reproduce this with other object?

you must use two sided lighting for those meshes which the sun shines through them.

click on your mesh then go to details panel and under lighting section check use two sided lighting check box

and then build lighting