FAILED TO BIND TO PORT error on a Minecraft server
This error means the server, or a plugin, tried to use a port it doesn't own. Never change server-port yourself; the panel assigns it. Give plugins their own extra port from the Network tab.
- Difficulty:
- Beginner
- Time:
- 5 minutes
On this page
If the console shows **** FAILED TO BIND TO PORT!, often followed by java.net.BindException: Address already in use or Cannot assign requested address and "Perhaps a server is already running on that port?", the server or one of its plugins tried to open a network port it is not allowed to use. On Endercloud this almost always comes from a changed setting, not from another server.
Why it happens
server-portorserver-ipwas changed inserver.properties. Your server can only use the port the panel assigned to it.A plugin or mod uses the main port or a port that isn't yours. Web maps (Dynmap, BlueMap), voice chat, Geyser and query/RCON each need their own port.
Two parts of the server use the same port, for example Dynmap and voice chat set to the same number.
How to fix it
1. Put server-port and server-ip back
Never change server-port in server.properties. The panel assigns your port (you can see it in the address at the top of the panel) and may set it back on every start. A different number will not work.
Look at your server address in the panel header, for example
in6.endercloud.in:45568. The number after the colon is your port. It is also the port marked Primary in the Network tab.Open Properties (or Files →
server.properties).Make sure
server-portmatches that number.Leave
server-ipas the panel set it (empty or0.0.0.0). Do not put your server's public IP or domain there; that causesCannot assign requested address.Save and restart.
2. Give each plugin its own extra port
Your plan includes extra ports (allocations). Open the Network tab. It shows a line such as "You are currently using 1 of 3 allowed allocations"; that count includes your main port, which has the Primary badge. Click Create Allocation to add a port if you have one left, then put that port in the plugin's config:
Plugin or mod | Where to set the port |
|---|---|
Dynmap |
|
BlueMap |
|
Simple Voice Chat |
|
Geyser (Bedrock players) | Geyser's |
Use a different extra port for each plugin, then restart. Guides: How to add extra ports, Dynmap and BlueMap, Simple Voice Chat, Geyser and Floodgate.
3. Check query and RCON
If you turned on enable-query or enable-rcon in server.properties, their ports (query.port, rcon.port) must also be one of your ports from Network, and different from each other. If you don't need them, turn them off.
4. Restart cleanly
Use Stop, wait until the server shows Offline, then Start. If the error still appears with all settings correct, open a ticket.
Frequently asked questions
Can I use port 25565 so players don't need to type a port?
Not by changing server-port. A port-free address needs a dedicated IP (open a ticket, price on request), or you can use a free subdomain with an SRV record for Java players. See Free subdomain and dedicated IP.
The error mentions a port I don't recognise
Search your plugins or config folder for that number. The file that contains it belongs to the plugin or mod trying to use it.
Is the server still usable when a plugin fails to bind?
Often the server starts but that plugin's feature (map, voice chat, Bedrock join) doesn't work. Fix its port and restart.
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