Die Kamera macht die Einheit der schwarzen Bildschirm

Check the following:
There is a camera in the scene.
The camera gameobject is active
The camera component is enabled
The camera component's display is the same as the game window display
The camera's rect transform is inside teh game window 
(could be rendering outside game window bounds)

If these don't work, add your own answer.
MunchDuster