Crashes when load 3d world

We are making a android game.

There are three scenes. The first is the menu, the second is a movie (unity sprite animation and sound) and the last is a 3d world. In the menu there is a manager object (dontdestroyonload) that has a scene manager that loads the scenes.

When I start the game normaly (menu -> movie -> 3d World) then the game crashes when he loads the 3d world.

When I put the 3dworld scene as the first scene, it runs well. When I disable all codes the same problem happens. In the past it did work.

I think this has to do with the memory. I have only 1gb.

I tried many things. I try to put a emty scene when he loads the new scene and that I do "Resources.UnloadUnusedAssets();" but that doesn't work.

I try to do it without the scene manager.

When I do it with a emty scene it does work. and when the game starts at the 3d world he also works.

does anyone know what the problem could be? or something I shpuld try? Thanks. If you need to know, please ask