Fixing a Minecraft server that won't start

Work down this list — the console output tells you which one applies.

1. EULA not accepted

Console shows "You need to agree to the EULA". Fix: Accept the EULA.

2. Wrong Java version

Messages like "UnsupportedClassVersionError" or "class file version 65.0" mean the jar needs a newer Java than the server is running. Check the Startup tab for a Java-version variable and match it to your Minecraft version, or open a ticket and we'll change it.

3. Out of memory

"OutOfMemoryError" or the server being killed shortly after boot means the world, plugins or mods need more RAM than the plan allows. Remove heavy plugins, lower view-distance, or upgrade your plan.

4. Broken or incompatible plugin

Scroll up in the console to the first ERROR or Could not load line — it names the plugin. Remove it from /plugins (Files tab) and restart. Then reinstall a version that matches your server.

5. Corrupt world or config

If the crash mentions a region file or a YAML/JSON parse error, restore the last backup or edit the named file.

6. Port already in use

Only one process can use the allocation. Check the Network tab and make sure server-port in server.properties matches your primary allocation.

Still stuck?

Open a ticket and paste the last 50 lines of the console. See How to get support.