You’ve setup your server with playit.gg and are ready to play. You or another player might be getting the Unknown host this error when trying to connect. This error happens because the computer asks your ISP (Internet Service Provider), what the IP is, and the ISP is silly and reports it being unknown.
The Fix
You need to update your computer DNS server. How to update the DNS depends on what operating system you’re running. - Windows: Update your DNS server on Windows - MacOS: Update your DNS server on MacOS - Linux: Update your DNS server on Linux