Arma Reforger Config.json Troubleshooting Guide: Fix Common Errors

Is your Arma Reforger server failing to start? Getting JSON syntax errors? This comprehensive troubleshooting guide will help you identify and fix common config.json issues quickly.

Quick Diagnostics

Before diving deep, try these quick fixes:

1. Validate your config.json: Use our Free JSON Validator
2. Check syntax: JSON is case-sensitive and strict with formatting
3. Review server logs: Located in ServerProfile/logs/ folder
4. Verify ports: Ensure ports 2001 (UDP) and 17777 (optional A2S) are open
5. Test with minimal config: Start with bare minimum settings

Common Error Messages

"Server socket failed to bind"

Error in logs:

Failed to bind server socket to 0.0.0.0:2001

Causes:

• Port 2001 already in use by another application
• Another Arma Reforger server instance running
• Firewall blocking the port
• Incorrect bindPort value

Solutions:

1. Check if port is in use (Windows):

netstat -ano | findstr :2001

2. Check if port is in use (Linux):

sudo lsof -i :2001

3. Kill conflicting process or change port in config.json:

{
  "bindPort": 2002,
  "publicPort": 2002
}

4. Check Windows Firewall:
   • Allow ArmaReforgerServer.exe through firewall
   • Create inbound rule for UDP port 2001

"Failed to parse config.json"

Error in logs:

Failed to load server configuration from config.json
JSON parsing error at line X

Common JSON Syntax Errors:

Missing Comma:

{
  "bindPort": 2001    ❌ Missing comma
  "publicPort": 2001
}

Fix:

{
  "bindPort": 2001,   ✅ Added comma
  "publicPort": 2001
}

Trailing Comma:

{
  "bindPort": 2001,
  "publicPort": 2001,  ❌ Trailing comma
}

Fix:

{
  "bindPort": 2001,
  "publicPort": 2001   ✅ Removed trailing comma
}

Wrong Quotes:

{
  "name": "My Server"  ❌ Curly quotes from Word/docs
}

Fix:

{
  "name": "My Server"  ✅ Straight quotes
}

Use our JSON Validator to catch these automatically!

"Invalid scenario ID"

Error in logs:

Failed to load scenario: {INVALID_ID}
Unable to register game

Cause: Invalid or misspelled scenarioId in config.json

Solution: Use official scenario IDs from the game. To list all available scenarios, start the server with:

ArmaReforgerServer.exe -listScenarios

Official Scenario IDs (v1.2+):

{
  "scenarioId": "{ECC61978EDCC2B5A}Missions/23_Campaign.conf"  // Conflict (Everon)
}

Other options:

• {59AD59368755F41A}Missions/21_GM_Eden.conf - Game Master (Eden)
• {28F19BA03F77306A}Missions/22_GM_Arland.conf - Game Master (Arland)
• {DD4992AB3F9DF01C}Missions/24_Tutorial.conf - Tutorial

Pro tip: Generate config with correct scenario IDs using our Config Tool!

"Backend registration failed"

Error in logs:

Failed to register server with backend
Connection timeout

Causes:

• Internet connection issues
• Backend servers down (Bohemia Interactive)
• Incorrect publicAddress or publicPort
• Router/firewall blocking outbound connections

Solutions:

1. Check internet connection

2. Verify public IP is correct:

   • Leave publicAddress empty for auto-detection
   • Or set to your public IP explicitly

3. Test with minimal config:

{
  "bindPort": 2001,
  "publicPort": 2001,
  "game": {
    "name": "Test Server",
    "scenarioId": "{ECC61978EDCC2B5A}Missions/23_Campaign.conf",
    "maxPlayers": 16,
    "visible": true
  }
}

4. Check Bohemia Interactive server status:
   • Visit official forums or social media
   • Check community Discord for reports

"Mod failed to download"

Error in logs:

Failed to download mod: {MOD_ID}
Workshop connection error

Causes:

• Invalid mod ID
• Mod removed from Workshop
• Steam Workshop connection issues
• Mod doesn't support server-side installation

Solutions:

1. Verify mod ID is correct:

   • Get from Workshop URL: https://reforger.armaplatform.com/workshop/MOD_ID_HERE
   • Check in Workbench mod properties

2. Test mod locally first:

   • Subscribe in client
   • Verify it downloads successfully
   • Check for console errors

3. Remove problematic mod temporarily:

{
  "game": {
    "mods": [
      // Comment out or remove failing mod
      // {
      //   "modId": "PROBLEMATIC_MOD_ID",
      //   "name": "Broken Mod"
      // }
    ]
  }
}

4. Check mod compatibility:
   • Ensure mod version matches server version
   • Verify mod supports dedicated servers
   • Check for known issues in mod description

Performance Issues

Server FPS Dropping

Symptoms:

• Server FPS below 20
• Players experiencing lag
• High CPU usage

Solutions:

1. Limit server FPS:

-maxFPS 30

2. Reduce view distances in config.json:

{
  "game": {
    "gameProperties": {
      "serverMaxViewDistance": 1600,
      "networkViewDistance": 1000
    }
  }
}

3. Check AI limit:

{
  "operating": {
    "aiLimit": 20
  }
}

Full optimization guide: Server Optimization

Memory Leaks

Symptoms:

• RAM usage constantly increasing
• Server crashes after several hours
• Performance degrading over time

Solutions:

1. Set up automatic restarts (daily at 4 AM):

Windows (Task Scheduler):

taskkill /F /IM ArmaReforgerServer.exe
timeout /t 5
start "" "C:\Path\To\ArmaReforgerServer.exe" -config config.json

Linux (cron):

0 4 * * * systemctl restart arma-reforger

2. Monitor memory usage:

   • Windows: Task Manager → Performance
   • Linux: htop command

3. Remove memory-intensive mods

4. Update to latest server version

Network Issues

High Ping / Latency:

Checks:

• Verify sufficient upload bandwidth (see table below)
• Test with fewer players
• Reduce networkViewDistance

Packet Loss:

Test with:

ping -t YOUR_SERVER_IP  # Windows
ping YOUR_SERVER_IP     # Linux

Solutions:

• Use wired Ethernet (not Wi-Fi)
• Check for ISP throttling
• Enable QoS on router

Port-Related Issues

Required Ports

Port Forwarding Validation

Test port forwarding:

1. Visit https://www.yougetsignal.com/tools/open-ports/
2. Enter your public IP and port 2001
3. Should show "open"

Router configuration:

• Forward external port 2001 → internal IP:2001
• Use UDP protocol
• Create separate rule for TCP if needed

Firewall Configuration

Windows Firewall:

netsh advfirewall firewall add rule name="Arma Reforger Server" dir=in action=allow protocol=UDP localport=2001
netsh advfirewall firewall add rule name="Arma Reforger Server" dir=in action=allow protocol=TCP localport=2001

Linux (UFW):

sudo ufw allow 2001/udp
sudo ufw allow 2001/tcp
sudo ufw allow 17777/udp  # Optional A2S

Configuration-Specific Issues

BattlEye Problems

Server won't start with BattlEye:

{
  "game": {
    "gameProperties": {
      "battlEye": false  // Disable temporarily for testing
    }
  }
}

Note: Disabling BattlEye may attract cheaters. Only use for private/testing servers.

Cross-Platform Issues

PS5 players can't connect:

Verify cross-platform is enabled:

{
  "game": {
    "crossPlatform": true
  }
}

Or specify platforms explicitly:

{
  "game": {
    "crossPlatform": false,
    "supportedPlatforms": ["PLATFORM_PC", "PLATFORM_XBL"]
  }
}

Important: Check that all mods support cross-platform!

Full guide: PS5 Cross-Platform Setup

Admin Password Not Working

Common mistakes:

1. Spaces in password (NOT SUPPORTED):

{
  "game": {
    "passwordAdmin": "my admin pass"  ❌ Has spaces
  }
}

Fix:

{
  "game": {
    "passwordAdmin": "myadminpass"  ✅ No spaces
  }
}

2. Wrong login syntax:

   • Correct: #login yourpassword
   • Wrong: #login yourpassword (extra space)
   • Wrong: /login yourpassword (wrong prefix)

3. Case sensitivity: Passwords ARE case-sensitive

Scenario Won't Load

Check scenario file exists:

• Verify scenario ID is correct
• Check for mod dependencies
• Ensure scenario version matches server version

Test with vanilla scenario:

{
  "game": {
    "scenarioId": "{ECC61978EDCC2B5A}Missions/23_Campaign.conf"
  }
}

If vanilla works, problem is with custom scenario/mods.

Advanced Troubleshooting

Enable Detailed Logging

Add startup parameter:

-logStats 60

This logs performance metrics every 60 seconds to ServerProfile/logs/.

Debug Mode

For development/testing, enable verbose logging:

-logLevel Verbose

Warning: Generates large log files. Don't use in production!

Validate Server Files

Steam (Windows):

1. Library → Tools → Arma Reforger Server
2. Right-click → Properties
3. Local Files → Verify Integrity

SteamCMD (Linux):

steamcmd +login anonymous +app_update 1874900 validate +quit

Config.json Best Practices

1. Use JSON validator before every server start: Validate Here
2. Backup working config before making changes
3. Test changes locally first
4. Use version control (Git) for config tracking
5. Document custom settings with comments (in external file)

Minimal Working Config

When troubleshooting, start with this minimal config:

{
  "bindPort": 2001,
  "publicPort": 2001,
  "game": {
    "name": "Minimal Test Server",
    "scenarioId": "{ECC61978EDCC2B5A}Missions/23_Campaign.conf",
    "maxPlayers": 16,
    "visible": true,
    "gameProperties": {
      "fastValidation": true
    }
  }
}

Then add settings one at a time to identify the problematic configuration.

Error Code Reference

Getting Help

If you're still stuck after trying these solutions:

1. Validate your config.json: Use Our Validator
2. Generate fresh config: Config Generator Tool
3. Check server logs: Share relevant errors in support channels
4. Community support: Join Our Discord
5. Official docs: Bohemia Interactive Wiki

Prevention Tips

Before every server start:

• ✅ Validate config.json syntax
• ✅ Backup working configuration
• ✅ Test mods individually
• ✅ Check server logs from previous session
• ✅ Verify port forwarding
• ✅ Monitor server resources (CPU/RAM)

Regular maintenance:

• Update server files weekly
• Clean old log files monthly
• Review and update mods
• Optimize based on performance logs

Quick Reference Commands

Check Server Status

# Windows
tasklist | findstr ArmaReforgerServer

# Linux
ps aux | grep ArmaReforger

View Live Logs

# Windows PowerShell
Get-Content -Path "ServerProfile\logs\latest.log" -Wait -Tail 50

# Linux
tail -f ServerProfile/logs/latest.log

Kill Server Process

# Windows
taskkill /F /IM ArmaReforgerServer.exe

# Linux
killall ArmaReforgerServer

Helpful Tools

• JSON Validator: Validate Config Here
• Config Generator: Create Config Here
• Server Setup Guide: Full Setup Tutorial
• Optimization Guide: Performance Tips

Last Updated: November 2025

Still having issues? Use our JSON validator to catch errors automatically!