Common errors in the console
What the usual error lines in your server's console mean, and how to fix each one.
The error lines owners see most in the console, and the fix for each.
Can't keep up! Is the server overloaded?
The server fell behind its 20 ticks a second, so players feel lag. One line after a restart is normal; many every minute is a problem.
- Check TPS and memory on the Overview.
- Lower the view and simulation distance in Settings.
- Limit mob farms and clear dropped items.
- Remove heavy plugins.
- On a paid plan, pre-generate the world.
java.lang.OutOfMemoryError
The server ran out of memory and may freeze or crash. Lower the view distance, remove heavy plugins and big farms, or move to more memory. Raising memory in Java flags does not help: the plan's limit still applies.
UnknownDependencyException or "missing dependency"
A plugin needs another one that is not installed, for example Vault. The line names it. Install it from Plugins and restart.
NoSuchMethodError, NoClassDefFoundError or "Unsupported API version"
A plugin was made for another Minecraft or Paper version. Update it to the build for your version, remove it, or switch version.
UnsupportedClassVersionError
A plugin was built for a newer Java than ours (Java 25). You cannot change Java. Install the build for your Minecraft version, or remove it.
InvalidConfigurationException or "while parsing a block mapping"
A .yml file has a mistake, usually a tab instead of spaces, a missing space after a colon, or an
unclosed quote. The line names the file and line. Fix it in Files, or
restore that file from a backup.
You are not white-listed on this server
The whitelist is on and the player is not on it. Add them on Players or turn the whitelist off.
Outdated client or Outdated server
The player's version does not match. Turn on Let older Java versions join in Settings for older players. See Versions and software.
Failed to read level.dat, or chunk errors
Part of the world could not be read, often after a force stop or a bad upload. Restore a recent backup; Restore into a new copy lets you check it first.