American Truck Simulator Server Troubleshooting

Fix common ATS server problems — version mismatch, server packages errors, connection issues, and GSLT crashes.

Common Issues

server_packages.sii and server_packages.dat are missing from the server directory. These are required for the server to start.

Fix: Export them from your game client — see Mod Setup.

The game client and server must be on the exact same version. Server updates can lag behind client updates by days.

Fix: Downgrade your game client via Steam Betas tab, or wait for the server update. See Version Mismatch.

Port forwarding is not configured. The ATS server does not handle NAT punching.

Fix: Forward TCP+UDP on ports 27015 and 27016. See Ports Reference.

Wrong App ID used when creating the GSLT token.

Fix: The GSLT must use App ID 270880 (base game), NOT 2239530 (server). Regenerate at Steam Game Server Management.

Server losing its Steam connection.

Fix: Check network stability. Verify the GSLT token is still valid. Regenerate if expired.

Fix: Re-export server_packages after any mod changes and re-upload both files. Players must have the same mods installed.

Fix: Run the server executable once — it auto-creates server_config.sii on first launch.

💡 Tip: Check server.log.txt in the server directory for detailed error messages.