I'm new and need help

I have recently thrown together my first map, it is a 1v1 map which I also made so that it can be played as a demolition map. When I try to run the map in game it says the map file is not found and then will allow me to fly around the map before crashing soon after. Does anybody know the solution to this problem, if so please message me.

I did that at first so I have 16 units below each spawn entity on each side currently, the only problems I can think of are that I used de_train/train_metalgrate01 as a floor texture which might not work with nav meshes, or that i set up my buy zone entity wrong