VR Architect scene - NavMesh problem

Dear UE Community.

I have a problem with creating my NavMesh ín a VRTemplate.

Everything works fine until I import new meshes (new buildings and pavement) into my scene. When I try to setup my navigation, my NavMesh only works on the first imported data (datasmith from ArchiCad). On the new importation doesnt show the green path of NavMesh.
Tried to insert an additional NavMesh, but aint working.

Any ideas why my new meshes are excluded from navigation?

Thx a lot.

As far I know in a there can only be one single NavMesh in a map/level. To ‘include’ your mesh in the navigation, select it and uncheck ‘Can Ever Affect Navigation’ in the mesh details.