Common Issues & Solutions
This page covers the most common problems you might encounter and how to fix them quickly.Server Won’t Start
”EULA not accepted”
Error:- Open
eula.txtin your file manager - Change
eula=falsetoeula=true - Save and start the server
”Port already in use”
Error:- Another process is using the port
- Check for duplicate server instances
- Try a different port in
server.properties - Contact support if the issue persists
”Java version incompatible”
Error:| Minecraft Version | Required Java |
|---|---|
| 1.17 - 1.20.4 | Java 17+ |
| 1.20.5+ | Java 21+ |
| 1.16.5 and below | Java 8 or 11 |
”Out of memory”
Error:- Check your RAM allocation in startup settings
- Increase Xms and Xmx values
- Use Aikar’s flags
- Don’t over-allocate (leave 1-2GB for the OS)
Server starts but immediately stops
Possible Causes:- Corrupted server files → Reinstall server software
- Plugin/mod conflict → Remove recently added plugins/mods
- Configuration error → Check logs for specific errors
- RAM too low → Increase allocation
/logs/latest.log for error messages.
Connection Issues
”Can’t reach server” / “Connection refused”
Server is offline
Server is offline
Check your panel—is the server showing as “Online”?
Wrong IP/port
Wrong IP/port
Verify you’re using the correct address and port from your panel.
Firewall blocking
Firewall blocking
If on a restricted network (school, work), the firewall may block Minecraft.
Server still starting
Server still starting
Wait a minute—the server might still be booting up.
”Connection timed out”
Causes:- Server is crashed or frozen
- Network issue between you and the server
- Packet loss on your connection
- Check if the server is running
- Try restarting the server
- Test your own internet connection
- Try from a different network
”Outdated client” / “Outdated server”
Your Minecraft version doesn’t match the server. Solutions:- Change your client version in the launcher to match
- Install ViaVersion to allow multiple client versions
”You are not whitelisted”
The server has a whitelist enabled and you’re not on it. Solutions:- Ask the server owner to add you
- Owner can add you:
/whitelist add YourUsername
”Disconnected: Flying is not enabled”
You moved too fast (lag or hacks detection). Solutions:- Enable flying in
server.properties:allow-flight=true - Adjust anti-cheat sensitivity
- Check player’s connection quality
World & Data Issues
World not loading / Corrupt chunks
Symptoms:- Specific areas crash the server
- Players get stuck in certain locations
- “Chunk loading error” in logs
- Restore from backup (recommended)
- Delete the corrupt chunks:
- Use MCA Selector to identify bad chunks
- Delete specific region files from
/world/region/
- Regenerate the area:
- Delete the region file (e.g.,
r.0.0.mca) - The server will regenerate it
- Delete the region file (e.g.,
Player data lost
Symptoms:- Player spawns at world spawn instead of their bed
- Inventory is empty
- Stats/achievements reset
- UUID changed (username change + offline mode)
- Corrupted playerdata file
- Different worlds being loaded
- Check
/world/playerdata/for the player’s file - Restore from backup if available
- If using offline mode, username changes reset data
”Level name contains invalid characters”
Solution: World folder names should only contain letters, numbers, and underscores. Rename your world folder and updateserver.properties:
Plugin Issues
Plugin not loading
Check console for errors
Check console for errors
Look at startup logs for error messages mentioning the plugin.
Wrong server type
Wrong server type
Bukkit plugins don’t work on Vanilla, Forge, or Fabric servers.
Missing dependencies
Missing dependencies
Some plugins require other plugins. Check the plugin page.
Version incompatible
Version incompatible
The plugin may not support your Minecraft version.
It's a mod, not a plugin
It's a mod, not a plugin
If you see “Invalid plugin.yml”, you downloaded a Forge/Fabric mod, not a Bukkit plugin.
Plugin commands not working
Causes:- Missing permissions → Use LuckPerms to grant permissions
- Wrong syntax → Check the plugin’s documentation
- Plugin not loaded → Check
/pluginsfor errors - Conflicting plugins → Another plugin may be overriding
Config changes not applying
Solutions:- Make sure you saved the file
- Use the plugin’s reload command:
/pluginname reload - Or restart the server
- Check for YAML syntax errors (use yamllint.com)
Performance Issues
Server using 100% CPU
Causes:- Too many entities
- Chunk generation during exploration
- Plugin running intensive operations
- Infinite loops in plugins
- Create a Spark profiler report:
/spark profiler - Identify the cause in the report
- See Diagnosing Lag
Server using all RAM
Not always a problem! Java uses available memory for caching. When it IS a problem:- Frequent garbage collection pauses
- “Out of memory” errors
- Increasing memory usage over time (memory leak)
- Use Aikar’s flags
- Don’t over-allocate RAM
- Check for memory leaks in plugins
- Schedule regular restarts
TPS drops during specific events
| Event | Likely Cause | Solution |
|---|---|---|
| Player joins | Chunk loading | Pre-generate world |
| Combat | Entity AI | Reduce mob counts |
| Redstone activation | Redstone tick | Limit complex circuits |
| Plugin command | Plugin performance | Update/replace plugin |
| Day/night change | Mob spawning | Reduce spawn limits |
Console Errors
”Reached maximum entity size”
Too many entities in one area. Solutions:- Kill entities:
/kill @e[type=!player] - Install ClearLagg
- Reduce spawn limits
”Can’t keep up! Is the server overloaded?”
Server can’t maintain 20 TPS. Solutions:- Follow optimization guide
- Reduce view distance
- Pre-generate world
- Upgrade server plan if hardware-limited
”Unknown command”
For players
For players
- Player lacks permission for the command
- Plugin providing the command isn’t installed/loaded
- Command syntax is wrong
In console
In console
- Don’t include the
/when typing in console - Plugin isn’t loaded
- Wrong command syntax
”Internal Exception: java.io.IOException”
Player’s connection was terminated unexpectedly. Causes:- Player’s internet dropped
- Server network hiccup
- Timeout due to lag
Quick Reference: Error Solutions
| Error | Quick Fix |
|---|---|
| EULA not accepted | Set eula=true in eula.txt |
| Port in use | Change port or stop duplicate servers |
| Out of memory | Increase RAM allocation |
| Connection refused | Verify server is running + correct IP |
| Outdated client | Match client version or install ViaVersion |
| Plugin not loading | Check dependencies and version compatibility |
| World corruption | Restore from backup |
| TPS dropping | Run Spark profiler, reduce entities |
| 100% CPU | Profile with Spark, identify culprit |
Still Need Help?
If your issue isn’t covered here:- Check the logs -
/logs/latest.logoften contains the answer - Search the issue - Google the exact error message
- Ask in Discord - Our community can help
- Contact support - Open a ticket with log files attached