Game crashes when playing through a VPN.

Hello everyone. I've been playing Heroes since the second installment and am a big fan of the third, just like a few of my old friends. Recently, we decided to set up a VPN so that we could play Heroes in the evenings. I won't go into too much detail about our efforts, but we settled on OpenVPN, with login using a unique certificate, and each certificate owner has a unique IP address. The version is Heroes of Might and Magic III Complete HD mod. The Windows versions are 10, 8, and 7 (mostly 10, but even when running from the same OS, there are still problems). The game crashes regularly for different users (crashing with a system error). The game freezes when sending or receiving data. It's impossible to play. Please help with the configuration. We've already tried a lot of things, including IPX wrapper and disabling UPnP, but nothing helps. If there's a manual, possibly for another program, please let me know where to find it. Sincerely, a fan of the third Heroes game. P.S. I can provide all the necessary data, a link to the repack we're using, our routers, dxdiag, or any other information.