My server won't start or keeps crashing

Start with “Why did it stop?”

When a server crashes or fails to start, the Console shows a Why did it stop? card. It reads the log, tells you what went wrong in plain words, and offers at most one fix the panel can apply for you. For example, it can:

• Turn off a plugin or mod that breaks the start.
• Roll back a plugin or an update that came right before the crash.
• Switch to the Java version your Minecraft version needs.
• Give the server more of its plan’s memory.
• Restore a recent backup.

Click Fix it to apply the fix, then start the server. Every fix has an Undo. If the card doesn’t show up, click Why did it stop? above the console while the server is offline.

Note

Before the AI reads your log, the panel removes chat, player names and IP addresses from it.

Fix it by hand

If there’s no fix on the card, or you want to understand the problem:

1. Open Console and scroll to the last error before the server stopped. Click the error and use Ask AI for an explanation.
2. Think about what changed last. A new plugin or mod, an update, or a version change is the most common cause.
3. Undo that change. Remove the new plugin’s JAR from plugins or the mod from mods, or restore the backup you made before the change.
4. Start the server again and watch the console.

Common causes:

What the log says	What to do
A plugin or mod name in the error, or “Could not load”	Remove or update that plugin or mod. Check it supports your Minecraft version and software.
“Unsupported class file major version” or a Java error	The server needs a different Java. Set Java version to Automatic on the Software tab of Settings.
“OutOfMemoryError”, or the server stops with no error	It ran out of memory. Remove heavy mods or plugins, or upgrade the plan.
A config file name and “while parsing” or “mapping values”	A YAML file has a typo, often a missing space or a tab. Open the file in Files and use History to go back to the version before your edit.
“Failed to bind to port”	Set server-port back to 25565 in server.properties.
The world fails to load after a version change	You may have moved the world to an older version. Restore the backup from before the change.

Hand it to Byte

Click the error and choose Ask Byte to fix it. Byte reads the logs and files, explains the problem, and makes the fix after you approve it.

A new server is stuck installing

The panel retries installs that get stuck. Give a new server up to 15 minutes. If it still says it’s installing after that, open a ticket.

Still stuck?

Click Share on the console to upload the log to mclo.gs, then open a ticket with the link. See get support.