Direct answer
Find the process already using the configured port or stop the duplicate server instance before changing ports.
What it means
The operating system refused the server bind because another process is already listening on the same local address/port combination.
This is the operating-system bind error that says some process already owns the port. If Minecraft itself prints “Failed to bind to port,” also check `server-ip` and use the separate bind-error guide.
If you are a player
- This is a server-side startup problem. Send the owner the exact panel/console error; reinstalling your game client will not fix it.
If you run the server
Targeted diagnosis: Check whether another Java process or service already owns the intended listener. On Linux, run ss -ltnp (or sudo ss -ltnp for process names) and look for the address/port in the bind error.
- Find which process is already listening on the Minecraft address/port and whether a duplicate server instance is still running.
- Stop the unintended listener or choose a deliberate unused port; do not run two servers on the same IP/port.
- Leave
server-ipblank unless you have a specific multi-interface reason to bind it. - Restart once and confirm the server reports a successful bind before debugging client connectivity.
Fix and verify: Stop only the process you have identified, or change the server port deliberately; do not kill every Java process. Check the panel for duplicate start attempts, and verify the new port is actually allocated and reflected in DNS/firewall rules.
References
Use the documentation for the exact software and release you run. These sources support the settings or diagnostic behavior used in this fix.
- Oracle Java launcher reference
- PaperMC: Getting started / Java requirements
- PaperMC: Basic troubleshooting
Related fixes and guides
Help us improve this article
Tell us what is missing, unclear, outdated, or incorrect. You can also suggest something we should add.