so i have a custom map i made, gave the map to my friend and he installed in in the Galaxy Dir, as did i (we can both play the game in Single Player mode) when i try to host a game, he logs into it for a second, then gets kicked while it tells him "you do not have the neccessary game files for this this game" we have no mods running, and non-custom maps work just fine.
How do you play a custom map online?