From position against stockfish doesn't work.

I wanted to play this position: 4k3/8/8/8/8/8/8/1N2KB2 w KQkq - against stockfish 8 to learn this endgame, but when started the game, the game didn't show up. Is there a maximal amount of games you can have in progress? I have 5 games in progress, but I think that isn't the problem, or can't you play an winning position against stockfish?

It worked for me: lichess.org/WJtRgJiF

Everything has some limit, although I don't know what the limits are.

@Toadofsky how many games did you had in progress? (like correspondence)

These posistions are banned because ultrabullet guys practised speed on them

@limponis thanks, but why can toadofsky still do them?