Web Player crash on load scene

I have a very simple home screen (NetworkManager and NetworkManagerHUD) which then leads into loading the scene I have set as OnlineScene in NetworkManager.

When I click to create a Local game, the game locks up and freezes just before loading the next scene. I lock the mouse on Start() of the 2nd scene as it is FPS, and this happens in the Web player before the game crashes, so it must be getting so far and then crashing.

Any ideas why this would happen, as it loads fine in the editor and windows standalone?

Found out what was wrong - hopefully this will help others in my situation:

The NetworkManager script had a different Prefab in it’s spawnable objects list to what was being called in the spawning script in Scene 1.