Grey Screen with Streaming

[Holy Avatar]

During playing games I stream to my friends. Often they have a grey screen.
Does this mean that Steam can't stream again due to too many users or is it due to other technical reasons? It works quite often. I just had a situation where someone could see the game. And then when I turned it off and turned on the next game, it turned grey again. I went back to the game that worked, but that was also grey.

We both have Windows 10. Restart doesnt help.