Hosting for steam/gog crossplay doesnt work without UPNP

[medea_fleecestealer]

Grim Dawn - Common Issues and Solutions

Common Multiplayer Issues and Solutions UPnP This is a technology that allows an application (like Grim Dawn) to communicate with your router. If your router supports UPnP (most do), Grim Dawn can tell your router to allow other people to connect to your computer when you are hosting a game. Why is this needed? Routers by default are designed to BLOCK anyone connecting to your computer. This is a security thing. You don’t want random/malicious computers connecting to your computer unless you …

Though I’m confused whether they can or can’t join your games. If they can’t see if anything in that link helps. If they can, what’s the problem?