The image is not clear about what happens - why is he getting stuck? Is there a collider where the post is?
If your game is Point And Click, you don't need wall colliders and you can safely remove it. If you do need them, try widening the hole in the NavMesh, reducing the size of the wall collider, or reducing the radius of the player's Capsule Collider.
But the floor is a collider too, no? Are there holes in the collider that match the holes in the geometry? Try placing a plane down to cover the whole floor - so long as the NavMesh is the same, the player should still navigate around the holes.
In that case, it's likely an issue with precision rather than collision. Have a read of Section 3.11 of the Manual - it gives an explanation on what I think is going on, and some suggestions on how to combat it.
Comments
If your game is Point And Click, you don't need wall colliders and you can safely remove it. If you do need them, try widening the hole in the NavMesh, reducing the size of the wall collider, or reducing the radius of the player's Capsule Collider.