Plutonium

So 3 of my friends were playing a High Round on Der Riese and we want to keep playing but one of us is getting bored and wants to take a sleeper (aka. Pausing my game on co-op), so all my friends left the game and once they left, i paused my game overnight and we can continue playing tomorrow, but then the next morning, when my friends were trying to connect to my game, they get blackscreen and the loading bar stop when it almost reached to the end and then a minute later they were timed out so none of my friends can't join my game so i have to end the game but when i host another game, looks like my friends can join my game now and i don't know why this happened. so is there any fix to this?

i have the same problem too, i was going for high round on der riese with 4 players and then i leave my pc on overnight and when i come back, my friends can't join back and they got blackscreen