Capsule Collider

When i run(with my character witch has capsule collider) into a box(that ofcorse has a box collider) that’s smaller than me for a half, my character just goes over that box, like it climbs over the box collider. Can i do something about this ?
HERE’S BETTER EXPLAINATION, IT MAY HELP YOU UNDERSTAND MY PROBLEM:

http://postimg.org/image/57bupnur3/

And btw. doesen’t happen when the box is bigger

thats why caplsule collider exists, if you dont want this behavior to happen mess with the
Radius & the Height of the capsule collider or just remove the capsule collider and add box collider