Why can't my enemies walk up an incline?

Hey all,

I was hoping someone could provide some insight to a problem I am having in my game. Currently I have my enemies spawning throughout my scene, and I have a bridge that links the two sides of my scene together. On this bridge there is a slight incline on each side and it seems as though my enemies are unable to walk over it. Right now my enemies are setup as navmesh agents; on them I have attached a simple box collider that wraps around their body, as well as a rigid body component with gravity enabled. I assume the problem may have something to do with the baked navigation settings, or the actual navmesh agent. If anyone has run into a similar problem I would really appreciate some advice.

Thanks!

I think its why upright characters normally use Capsules. The corners of your box could be getting stuck on the incline?