Issues with proper Teleport on Mesh

Hi I am rather new to the UE,

I have been given a static mesh from my University of a building.
The Building had no collisions, which means I had to creat a collision for the floor mesh. Then I created the pathing in my navigation mesh and it shows green.
So far so good, however if I try it now with the occulus I am unable to teleport at all, unless I create a new floor mesh with the Unreal tool, on which it works fine.
This seems rather odd to me and I am unable to identify the Problem after all kinds of tests on my end.

Thanks in advance.