full party not joining games

[Wisercartoon]

Alright, so, whenever i try to play as a party with my friends (usually three people) one of us either gets disconnected (connection timed out) or has to reload the multiplayer menu. I have tried things to fix this issue such as network changes or resetting my graphics (this worked once for some reason), but since then a full party of three has never been able to work. So ya is there any obvious or non-obvious fix for this?