Minecraft Troubleshooting

Solutions for common Minecraft Java server issues on CoreSynth.

Overview

Common Issues

Missing/Invalid eula.txt

Cause: EULA not accepted.

Solution:

1. In the control panel, go to File Manager
2. Open eula.txt
3. Change eula=false to eula=true
4. Save and restart server

Invalid Session / Failed to Verify Username

Cause: Using a cracked client with online-mode enabled.

Solution:

1. In the control panel, open server.properties
2. Set online-mode=false
3. Restart server

Warning: With online-mode=false, cracked clients can connect but skins will not work.

Server Lag / Performance Issues

Cause: Insufficient RAM, too many plugins, or poor view-distance settings.

Solution:

1. Reduce view-distance:

view-distance=6
simulation-distance=6

2. Check RAM usage:

   • In the control panel, go to System → Resource Usage
   • If RAM is at limit, upgrade the server

3. Optimize plugins:

   • Remove unused plugins
   • Use Paper or Purpur server software

View-Distance Optimization

Cause: Too high view-distance value is overloading the server.

Recommended Settings:

view-distance=8
simulation-distance=6
entity-broadcast-range-percentage=50

Plugin/Mod Compatibility Issues

Cause: Plugin is not compatible with Minecraft version or server software.

Solution:

1. Verify Minecraft server software version (Paper, Spigot, Vanilla)
2. Check plugin documentation for supported versions
3. Update plugin to latest version
4. Check logs (logs/latest.log) for compatibility errors

Server Crashes — OutOfMemoryError

Cause: Insufficient RAM allocated to server.

Solution:

1. In the control panel, go to Startup
2. Increase Memory value (minimum 2 GB for smaller servers)
3. Restart server

Tip: For 1-10 players, we recommend 2-4 GB RAM.

Server Crashes — Tick Rate Issues

Cause: Server cannot keep up with world ticks.

Solution:

# In server.properties
max-tick-time=-1

In the control panel, edit startup parameters:

java -Xmx2G -Xms2G -XX:+UseG1GC -jar server.jar

Cannot Connect to Server

Cause: Firewall, wrong port, or server not running.

Solution:

1. Check server status:

   • In panel, verify server is running (green indicator)

2. Check port:

   • Verify you are connecting to the correct port
   • Default port: 25565

3. Firewall settings:

   • In the control panel, go to Security
   • Ensure port 25565 is allowed

Diagnostic Commands

Run these commands in the server console for diagnostics:

Next Steps

• Minecraft Setup — Server setup guide
• Game Servers — All supported games

Need help? Open a support ticket  or ask Alex.