if there is no navmesh, i dont know why but ye maybe its broke

Press / to open the console, then type "navmesh_generate_cheap" or "navmesh_generate_cheap_expanded" (without quotation marks) in the console that appears, & finally press Enter. This will generate a navmesh upon resuming the game, allowing TF2 bots & other NPCs that need a navmesh to function when complete. You only need to generate a navmesh for a map once, & the navmesh will be loaded alongside the map on future servers & singleplayer games created on that device using that map.

I hope my advice helps!