So today I tried to get Halo 2 running in two PCs connected through an ethernet cable in a LAN game (and before you ask, yes that worked for tests with other games and LAN tools)... and I get the "Impossible to Join" message.
Changed ports and used the lan/wan ip option in config.ini, disabled windows defender and firewall on both PCs, and both can ping each other through CMD. The computer that's not hosting can see the game in the lobby but gets the same message. Happens when either does that.
Changed ports and used the lan/wan ip option in config.ini, disabled windows defender and firewall on both PCs, and both can ping each other through CMD. The computer that's not hosting can see the game in the lobby but gets the same message. Happens when either does that.