Posts from Problem with online gameplay. Auto-translated

We decided to play with friends in a 4v3 match. One of us had an old disk with Heroes and three expansions... We patched it to version 1.6 for three players, and it worked fine. However, for the fourth player, the checksum didn't match... We reinstalled it, but it still didn't work... We found a key from a friend for the old version, but the disk didn't work either... We all have the game working fine... Recently, he was able to connect to a different server, but he couldn't connect to ours... What's the problem, and how can we fix it?:(

Are the three expansions add-ons to the original game? If so, you won't be able to see each other, and the keys won't help here.