Unknown Host
Re-enter unstable-events.net exactly. Remove https://, spaces, a slash, or an appended port. Check the spelling of “unstable-events” before changing DNS or network settings.
Outdated client or server
The client and server must be in the supported range 26.3–1.21.11. If the launcher updated you to a newer release, create an installation for a supported version and try again.
Timeout or connection refused
This often means the server is restarting or your connection dropped. Check announcements, restart Minecraft, and retry. Public servers do not normally require router port forwarding.
Sign-in or authentication error
Sign out and back in through the official Minecraft Launcher. Never enter your Microsoft credentials on a page linked by another player or a bot.