Can't HOST/CRASH multiplayer lobby

When I join other people's lobby there is no problem. But when I have to create the lobby myself, I invite peoples and after a few seconds that someone tries to join, they get an error saying "the lobby does not exist" something like that. I'm still in the lobby like nothing happened but they can't join. My internet speed is very good: 800-500 download and around 200 upload, Ethernet connection.