Why does my Minecraft server crash?

If your Minecraft server crashes or will not start, the cause is almost always in the console or the log files. Below you can read where to look and what the most common causes are, from most to least likely.

Where to find the error

• Console: open your server in the game panel. Scroll up in the console to the first line with ERROR, Exception or Caused by.
• Logs: go to Files and open the logs folder. latest.log holds the last session.
• Crash reports: after a real crash Minecraft writes a file to the crash-reports folder. The cause is at the top.

Wrong Java version

Check: the console shows UnsupportedClassVersionError or class file version.

Fix: choose the right Java version at Startup and then Docker Image. See How do I change the Java version of my Minecraft server?

A plugin or mod does not work with your version

Check: the error names a plugin or mod, for example Error occurred while enabling ... or Mod ... requires ....

Fix:

1. Stop your server.
2. Disable the named plugin or mod by moving it out of the plugins or mods folder. You can also rename it, for example to name.jar.off.
3. Start your server. If it works, find a version of the plugin or mod that matches your Minecraft version.

If the error names nothing, remove half of your plugins or mods and test again. That way you quickly find the one causing the problem.

Not enough memory (RAM)

Check: the console shows OutOfMemoryError, or the server stops without a clear message while Memory in the console is close to the maximum.

Fix:

• Use fewer or lighter plugins and mods.
• Lower view-distance and simulation-distance in server.properties. See How do I reduce lag on my Minecraft server?
• If your server really does not fit any more, choose a larger plan.

The server hangs (watchdog)

Check: the console shows The server has stopped responding! or A single server tick took 60.00 seconds.

Fix: this is usually caused by a plugin, a mod or a large machine in the world. Make a spark profile to see what keeps the server busy. See How do I reduce lag on my Minecraft server?

Broken world or broken config file

Check: the error names a file in your world folder (for example region or level.dat), or a .yml file with a ScannerException or YAMLException.

Fix:

• For a .yml error: check the named file for indentation and quotes, or delete it so the plugin creates a new one.
• For a broken world: restore a backup.

EULA not accepted

Check: the console says You need to agree to the EULA in order to run the server.

Fix: open eula.txt in Files, change eula=false to eula=true and start your server again.

Still not working?

Open a ticket and include:

• the name of your server in the game panel
• your Minecraft version and server type (Paper, Fabric and so on)
• the error from the console or the crash report
• what you changed just before the crash