My first guess would be that you have a random collision object that is blocking your teleport. I had this happen when I imported two pieces of glass on either side of a stair, that I had attached together as one object, before I exported from my modeling program. Unreal enclosed them in one box, and it made it impossible to move between them. I simply removed the collision object and created two new ones.
If you used “auto generate collision”, it is likely that it enclosed your static mesh, that may be made up of multiple pieces, with one single collision. Unchecking “Can ever affect navigation” will not override this. Did you check your collision objects?
I had a few very small meshes which, when i turned “view collisions” had some very thin collision edges pointing out in all directions accross my map. It was very strange and i almost missed it!
But yeah, viewing collisions in the viewport helped!