Nav Mesh Bound Volume not working on a Static Meshe terrain


I made a landscape with Blender (yes, because I wanted a very low poly landscape) and I try to use a Nav Mesh Bound Volume for my AI but when I hit ‘P’, only the top of the trees appear in green. My whole terrain meshe is included in the Nav Mesh.
I do not what to do to get my NVBV working…


I precise I already try to do a full build before creating my navmesh and restart UE4.

I finally solved the problem by checking ‘Simulation Generate Hit Events’ on my terrain meshe.

Or make sure the timer for Set Timer is set to 1.