We've been trying to play multiplayer for a while now, and Vintage Story will just randomly... not connect? I'm asking here because I don't know if it's a bug, just that it happens apparently at random and there is no consistent fix. While our game is modded, we have tried it unmodded to identical results. It will work, people can connect, then suddenly with no change people can't connect, even during the same session with people already connected and are still playing.
The error is always the same:
Unable to connect to server.
A connection attempt failed because the connected party did not properly respond after a period of time, or the established connection failed because the connected host has failed to respond.
We have tried setting proper subnet routers, firewall rules inbound and outbound, UpNP/UNP/TNP settings, checking for stale UpNP, assigning manual IPs, restarting things, moving to a dedicated server, updating, downgrading, reinstalling, and prayer. Everything seems to have worked once or twice then never again out of dozens of attempts. Only the dedicated server host can connect without failure. Yet we know it can be done and done consistently by others, so... how?!