Collisions just suddenly stopped working, what could cause this?

Unity Engine
1

I have a character with a capsule collider and a box in front of it with a box collider, and for the longest time if i walked into the box, it would prevent the character from walking through it, however something i’ve done recently has broken this. No matter what i try my character can walk through the box now.

What could have caused this?

2

Are you sure that ‘box collider’ and ‘capsule collider’ are check marked in the inspector?

3

One possibility: Edit > Project Settings > Physics. Make sure that the layers that are colliding with each other are checked.