A Minecraft Java server may fail to start because of an incorrect version, plugin or mod error, missing dependency, damaged configuration, world problem, Java compatibility issue, or insufficient resources.
This guide explains how to troubleshoot a Down Side Hosting Minecraft Java server that will not start.
Open your Minecraft server in the Down Side Hosting server panel and select:
Console
Click Start and watch the messages that appear.
The console is usually the most important place to begin.
Look for messages containing:
ERROR FATAL Exception Failed Could not load Caused by: OutOfMemoryError UnsupportedClassVersionError
Do not focus only on the final line of the console.
The actual cause of the startup failure may appear several lines earlier.
Before changing anything else, think about what happened immediately before the problem began.
For example:
If the server worked immediately before one of these changes, investigate that change first.
Some Minecraft servers take longer to start than others.
This is especially true for:
Do not repeatedly press Start while the server is still performing a normal startup.
Watch the console to determine whether the server is still loading or has actually stopped.
A successful Minecraft startup normally ends with a message indicating that the server has finished loading and is ready for players.
If the process exits before reaching a normal ready state, check the errors immediately before shutdown.
A new Minecraft server may create:
eula.txt
Open the file.
If it contains:
eula=false
change it to:
eula=true
and save the file.
Then start the server again.
By changing this setting, you are confirming acceptance of the Minecraft End User License Agreement.
Make sure your server software matches the Minecraft version you intend to run.
This is especially important for:
Do not assume files built for one Minecraft release will work on another.
Verify that you are running the server software your files expect.
Common configurations include:
For example, Bukkit-style plugins belong on compatible plugin server software such as Paper, Purpur, or Spigot.
Forge or Fabric mods normally belong on the appropriate mod loader.
See:
Paper vs Purpur vs Spigot: Which Minecraft Server Should You Use?
If the server worked before adding a plugin:
plugins/
If the server starts normally, investigate the plugin's:
See:
An updated plugin may introduce:
If the problem began immediately after the update, restore your pre-update backup or previous compatible plugin version when appropriate.
See:
How to Update Plugins on a Down Side Hosting Minecraft Server
You may see errors such as:
Unknown dependency
Missing dependency
or:
Could not load plugin
Check the plugin documentation for required dependencies.
A plugin may require software such as:
Vault ProtocolLib PlaceholderAPI Another plugin library
Install the appropriate dependency and restart the server.
If a Forge, Fabric, or NeoForge server stopped starting after adding a mod:
mods/
If the server starts, check that mod's:
Forge, Fabric, and NeoForge are different modding systems.
A mod built specifically for:
Forge
should not normally be installed on:
Fabric
Likewise, Fabric mods should not normally be installed on Forge.
Verify the loader listed on the mod's official download page.
A mod-loading error may say something similar to:
Mod A requires Mod B
Install the required dependency using the version compatible with your:
See:
Some Minecraft mods are designed only for a player's client.
Examples commonly involve:
A client-only mod may prevent a dedicated server from starting.
Check the mod's documentation before installing it server-side.
If you are using a modpack, verify:
Whenever possible, use the modpack developer's official server pack.
See:
How to Install a Minecraft Modpack on a Down Side Hosting Server
Make sure the full server pack extracted successfully.
A modpack may require folders such as:
mods/ config/ defaultconfigs/ libraries/
and additional startup or configuration files.
Missing files can prevent startup.
An extracted server pack may accidentally look like:
server/
modpack/
mods/
config/
when the necessary files are expected directly in:
server/
mods/
config/
Check the modpack's installation instructions before moving files.
Some Minecraft, plugin, mod, or mod-loader versions require a particular Java version.
A common error is:
UnsupportedClassVersionError
This often means some software was built for a newer Java version than the server is currently using.
If the console indicates a Java compatibility problem and you are unsure what runtime your server should use, contact Down Side Hosting support with the complete error.
Customers do not normally edit Java startup arguments directly.
If your Minecraft server, modpack, or server software requires specific Java arguments, contact Down Side Hosting support.
Include:
See:
Minecraft Java Arguments and RAM Settings on Down Side Hosting
If the console displays:
OutOfMemoryError
the server may not have enough memory for the current workload, or a plugin/mod may be consuming excessive memory.
Down Side Hosting server RAM is determined by the hosting plan you purchased.
If the server genuinely needs additional memory, your server can be upgraded to more RAM.
See:
Java may keep allocated memory available for later use.
Do not determine that a server needs more RAM solely because the panel shows high memory usage.
Look for actual symptoms such as:
OutOfMemoryErrorIf the server stopped starting after editing:
server.properties
review your recent changes.
See:
Minecraft server.properties Configuration Guide
Pay particular attention to networking settings if they were changed.
Down Side Hosting Minecraft servers are assigned a port.
Your connection address normally looks like:
dsh.network:YOUR_PORT
Do not randomly change:
server-port=
because doing so can prevent the server from using the port assigned by the hosting environment.
The setting:
server-ip=
should normally be left as configured by the hosting environment.
Do not enter:
dsh.network
simply because that is the hostname players use to connect.
A console error may mention:
Failed to bind to port
or:
Address already in use
If this occurs on a Down Side Hosting server, verify that you have not manually changed the assigned networking settings.
If the configuration appears correct, contact support and provide the console error.
Plugins and mods often use configuration files such as:
config.yml
server.properties
or files under:
config/
If the server stopped starting immediately after editing a configuration file, restore the previous version and test again.
Plugins commonly use YAML configuration.
Incorrect indentation can cause errors.
For example:
settings: enabled: true message: "Welcome"
Look for console errors mentioning the configuration file and a line number.
See:
Minecraft and some plugins use JSON files.
A missing comma, quotation mark, or bracket can make a JSON file invalid.
If startup failed after manually editing a .json file:
Check:
server.properties
and:
level-name=
For example:
level-name=survival
expects the server's main world to be in:
survival/
The world should contain files such as:
survival/
level.dat
region/
See:
If startup fails while loading a specific world, the console may identify:
Do not delete the world immediately.
Create a copy or preserve the existing files before attempting repairs.
A modded world may rely on content provided by installed mods.
Removing those mods can cause warnings or errors involving:
If this happened after changing the mod list, restore the required mods or your previous backup.
If a backup previously worked but does not start after restoration, compare the current environment with the original one.
Check:
See:
How to Back Up and Restore a Down Side Hosting Minecraft Server
The current Minecraft log is normally located at:
logs/latest.log
This can be useful when the console scrolls too quickly or does not show enough history.
Look for the first meaningful error around the point where startup fails.
If Minecraft produced a crash report, check:
crash-reports/
Crash reports are especially useful for modded servers.
They may contain:
In a Java stack trace, look for:
Caused by:
There may be several of these sections.
The deepest relevant Caused by section can often provide a more useful clue than the final generic error.
When troubleshooting, avoid randomly deleting:
Those files may contain important server or player data.
Make a backup before removing anything that may be difficult to replace.
A full reinstall is rarely the best first troubleshooting step.
First determine:
Reinstalling without a backup can make recovery more difficult.
If the cause cannot quickly be corrected and you have a known-good backup, restoring it may be the fastest way to return the server to service.
Before restoring, consider backing up the current broken state as well.
That preserves the files for later troubleshooting.
See:
Check these in order:
latest.log.The server is probably encountering an error during startup.
Check the console and latest.log for the first meaningful error before the shutdown.
The plugin may be incompatible, missing a dependency, or built for a different Minecraft version.
Temporarily remove the plugin and test the server again.
The update may have changed:
Check the modpack's update notes and compare it with your previous working version.
Yes, if more memory is genuinely required.
RAM is determined by the Down Side Hosting plan you purchased, and you can upgrade your server to additional RAM.
Java arguments are managed by Down Side Hosting.
If you have a specific requirement, contact support with the arguments and the reason they are needed.
The server may be trying to use an incorrect or unavailable network address or port.
Do not randomly change networking settings.
Down Side Hosting servers should use the port assigned to that server.
Not as a first troubleshooting step.
Preserve the world and check the actual error first.
Provide:
latest.log when usefulProviding the error itself is much more useful than only saying:
My server won't start
If you cannot identify the startup error, send Down Side Hosting the relevant console output and server information.
Down Side Hosting provides Minecraft Java hosting with server panel access, file management, console controls, backups, and support.
Minecraft Java hosting starts at $2/month.
View Minecraft Java Server Hosting