can't host server

I create a server in Network and nobody can join, we installed hamachi but still cant join, PLEASE HELP

So for like 2 months I've been trying to figure out how to host a game and have my brother join. I really wanna play coop campaign with him and i found this tool on this page: https://halo2.online/threads/coop-mode-update.468/ So now I'm trying to host a server but every time I do i get this...