So I am trying to select the frame in order to zoom out a little as I normaly do, but somehow i can´t select it. I tried it in other files and it worked there. I recognized that there is normaly a clear black outline at the frame but in this case it´s somehow missing. What am I doing wrong?
I have the answer. I noticed that there was no camera in the layers I wanted to render. I simply had to additionaly select the original layer where the camera was placed in order to manipulate the camera view.