Minecraft server won't start: how to find the cause and fix it

A server that will not start nearly always says why. The reason is in the console, a few lines above the point where it stops, and it is usually one of a handful of causes: a plugin or mod that does not fit, the wrong Java version, a config file with a typo, or a world file that got damaged.

Work through this page from the top. Most servers are running again after the first two sections.

1. Read what the server says

Open the panel and look at the badge next to the server name. Offline with a Start button means the server stopped; click Start once and switch to the Console tab while it boots.

The top of the control panel showing the server Offline with the Start button — Offline: click **Start** and watch the console while the server boots.

In the Console tab, set the level filter to Errors. Only the red lines stay.
Look at the first error, not the last. The last lines are often a result of the first one.
Still unclear? Set the filter to Warnings as well; a warning just before the error often names the plugin or file.
Type a word from the error, such as a plugin name, in the search box above the log to see every line about it.

The console of the control panel with the level filter menu open, showing All levels, Info, Warnings and Errors — The level filter hides everything except the lines that matter. The search box next to it narrows it further.

Did the server stop before you opened the console? The full log of the last start is saved in the Files tab, in logs/latest.log. Older starts are kept next to it as .log.gz files, which the panel can extract for you.

The logs folder in the Files tab with latest.log and older log files ending in .log.gz — `latest.log` is the last start. Open it with **Edit** to read it, or **Download** it to send to someone who helps you.

2. Find your error in this table

What the log says	Cause	Fix
`Could not load 'plugins/Name.jar'` with `Unsupported API version`	A plugin made for another Minecraft version	Update the plugin, or disable it as shown below
`UnsupportedClassVersionError` or `class file version`	The server runs on an older Java than it needs	Pick a newer Java in Settings under Startup
`OutOfMemoryError: Java heap space`	The server ran out of memory while loading	Remove the heaviest mods or plugins, or move to a plan with more RAM
`Unknown dependency` or `requires` another plugin or mod	A plugin or mod needs another one that is not installed	Install the missing one, at a matching version
`Failed to bind to port` or `Address already in use`	The port in `server.properties` was changed	Set `server-port` back to the port the panel shows
`Exception reading` a `.mca`, `level.dat` or `region` file	Part of the world file is damaged	Restore your latest backup
`You need to agree to the EULA`	`eula.txt` says false	Open `eula.txt` in Files and set it to `eula=true`

Your error is not in the table? Copy the first red line into a search engine together with the word Minecraft. Almost every startup error has been hit by someone before, and the top result usually names the fix.

3. Disable a plugin that stops the server

When the log names a plugin, you do not have to delete it. Rename the file so the server skips it, start the server, and decide later what to do with it.

In the Files tab, open the plugins folder.
Click Rename on the plugin's .jar file and add .off to the end, for example BrokenPlugin.jar.off.
Start the server. It ignores every file that does not end in .jar.
Once you have a version that fits, upload it and delete the .off file.

The plugins folder in the Files tab with several plugin jar files and the Download and Rename actions — Each plugin is one `.jar` file in `plugins`. Renaming it to `.jar.off` turns it off without losing its settings folder.

No plugin named in the log, but the problem began after you added several at once? Turn off half of them, start, and repeat with the half that still fails. On a modded server the same trick works in the mods folder.

Before you change anything else, make a backup in the Backups tab. If a fix makes it worse, you can go straight back. Back up and restore your server shows how.

4. Fix a config file with a typo

A single wrong character in a config file can stop the server at boot. The log then names the file, often with a line number.

Open the file in the Files tab with Edit. For the main settings that is server.properties in the top folder.
Go to the line from the error. In .yml files, look for a tab instead of spaces, or a missing space after a colon.
Save and start the server again.

The top folder of the Files tab with server.properties highlighted — `server.properties` holds the main settings. Leave `server-port` as it is: the panel sets it for you.

Anything that is also offered in Settings, such as the server type or the Minecraft version, is safer to change there. The panel then writes the file for you, without a typo.

5. Check the server software and Java

After a change of Minecraft version, plugins and mods can stop fitting, and an old world can need a newer Java. Settings shows both in one place.

The Server software card in Settings with the server type set to Paper and the Minecraft version field — The server type and version live under **Server software**. Switching keeps your world, settings and play address.

Under Startup, the Java version shows which Java is recommended for your Minecraft version. A newer Java than needed is almost always fine; an older one will not start the server.
Changing the Minecraft version sets the matching Java again by itself.
Both take effect at the next restart, so start the server after saving.

Which Java version your server needs has the full list per Minecraft version.

6. When the world itself is damaged

A server that stopped during a save, or a world uploaded half, can leave a region or level.dat file damaged. The log then mentions reading one of those files. The quickest safe fix is your latest backup: stop the server, restore it in Backups, and start again.

No backup? Download the world folder first, so nothing gets lost. Then send us a message from the client area with the error line; we look at it with you.

Questions

My server starts and then stops after a minute. Is that the same problem?

Often, yes. Read the log in the same way: the error just before it stops names the cause. If it runs for a while first, lack of memory or a plugin that fails on its first task are the usual suspects.

Does the server restart itself when it crashes?

Yes. Crash watch on the Overview tab restarts the server when it crashes or stops responding. A server that fails at every start cannot be fixed by restarting, so then the log is where to look.

Can I undo a change that broke startup?

If you made a backup before the change, restore it in the Backups tab. Otherwise undo the change by hand: rename the new plugin to .jar.off, or put the old value back in the config file.

Do I lose my world when I switch server type to fix this?

No. Switching the server type in Settings keeps your world, your settings and your play address. Plugins made for another type may stop loading, which is expected.

Checked against Paper for Minecraft Java 26.2 and our control panel, September 2026. Written by the Cheapest Minecraft Hosting team, updated 28 September 2026.