In my game the fps controller can collide with floors that it can walk on but for some reason won’t collide with walls that have a box or mesh collider!
Please help this is stopping me from finishing the game!
Possible Things That COULD Fix it:
Check the tags/layers/Collision Matrix of the Walls and FPS Controller.
Check the FPS Controller’s character controller.
Scale the box collider correctly.
If all else fails, use a script to control collisions instead! 
Well Mesh Colliders can’t collide with other Mesh Colliders unless they’re both convex. Still, I don’t know what’s up with the box colliders. What kind of collider do you have on the fps controller?
You need to be more specific. Theres a number of things it could be.
Found out the problem is was a sprint script that disabled collision for some reason