Kata Seiko

Little info on the side for those of you interested: You can download and test Server 2022 for free for half a year (180 days). More info on Microsoft Windows Server Blog.

You can check if you have a provider NAT, that will make it impossible for your friends to connect to you:

You should have a website with your router. You can check how you can reach it with IP Config (Win+R, type "cmd" and click "Run", then type "ipconfig" and press Enter), just type the address listed as "standard gateway" into your browser. The website of your router will have an overview about how it is connected to the internet - I can't help you with finding that one, every router is different - and show you an "external" or "public" IP address. If you have an IP address in the 100 range, it's a clear indication that your ISP has a provider NAT (many newer ISPs have them because IPv4 addresses are in limited supply). You can also compare the address with ip4.me to see what your (global) public address is and compare that with the IP of the router. If that one differs from your router's reported public IP, you definitely have a provider NAT.

Maybe this helps.

You shouldn't require UPnP when you forwarded port 42420.. Is the target of your port forwarding set to the correct IP address?

The manual Wiki: Setting up a Multiplayer Server - Dedicated Servers on Windows just says to install the game and run the VintageStoryServer.exe - but the installer exe won't even start.

Does anyone have any experience with this yet?