help with split screen

Hi, can you please teach me how to use splitscreen? I activate the before and after but only the right side works well but the left side does not recognize the original configuration, it only gives me a black screen

FX execute in order of the technique list top to bottom.
If order of Before/After technique in technique list as followchange order to (hold down the left mouse button on technique name and drag up or down)

thanks, I worked