Cant walk through doorway mesh created in Blender

I created this mesh (screenshot below) in Blender, but for some reason my character can’t walk through it. The Mesh collider seems to match exactly with the rendered mesh.

I made sure the collider on my player is not too big etc.

Any ideas why this is happening?

Thanks.

Not sure what exactly you want but if you mean acting like an invisible object just remove the mesh collider.

If you want the door to be able to be bumped open, you will need to make sure or have its pivot point established which you can do using Gizmos, ad creating one like this demo vid shows. Creating Custom Pivots in Unity - YouTube.

Then simply add a rigid body with a box collider being sure to check the position and rotation options in rigid body the way you need them to be.

If you mean the whole arch itself, than there is something wrong with the model itself where the part where the door would go has a transparent piece, so in blender you want to check the part saying backface culling which you can find under Shading.