Error Codes › FAILED TO BIND TO PORT

FAILED TO BIND TO PORT

COAL-015 · Failed to bind to port

The Minecraft server could not claim its port on startup. What binding means, the three reasons it fails, and how to fix each one.

What it looks like in the log

[Server thread/WARN]: **** FAILED TO BIND TO PORT!
[Server thread/WARN]: The exception was: java.net.BindException: Address already in use: bind
[Server thread/WARN]: Perhaps a server is already running on that port?

What it means

On startup the server claims its port so it can accept connections. This message means the claim was refused. Almost always that is because another process already holds the port - see COAL-002 for finding and freeing it - but two other causes are worth knowing.

How to fix it

Something else has the port. The common case: kill the leftover java process, or change server-port.
The configured server-ip does not exist on this machine. If it is set to an address this machine does not hold - a public IP on a NATed VPS, or a stale LAN address - the bind fails. Leave server-ip blank; that is the correct value for nearly every server and means "listen on everything".
Permission on a low port. On Linux, ports below 1024 require root. Stay on 25565 or another high port.

This error is about the local machine only. If the server starts fine and players still cannot connect, that is a port forwarding problem instead - see the port forwarding guide.