How to play Heroes of Might and Magic III online via Hamachi?

Situation: VPN network All computers are pingable. Response time is approximately 70ms. The versions of the game are identical and have been copied. The game version is HOMM3TE (Tournament Edition). IP addresses differ only in the last digit. The players are using a VPN connection (verified). 1v1 games work perfectly. Everything runs without bugs. Problem: When a third player connects, they receive the error "IP address was not found," regardless of who the player is. I have considerable experience with workarounds that allow playing old games over a network. However, I have no idea what the problem is here. By the way, the same thing happens in Hamachi. I look forward to your answers.