BeamMP Server Troubleshooting

Fix common BeamMP server problems — auth key errors, connection issues, mod problems, and more.

Auth Key Errors

"No AuthKey Specified" — Key field is empty. Get one from Keymaster.

"Backend system refused server! Check your AuthKey" — Key is invalid, expired, or already running on another server. One key = one server at a time.

Server Not in Browser

Check Private = false in config
Check auth key is valid
Look for [WARN] Backend failed to respond to a heartbeat in console
Wait 1–2 minutes after startup

"Socket Error" / Stuck Connecting

Usually caused by corrupted or incompatible mod files, especially after a BeamNG.drive update.

Server fix:

Temporarily rename Resources/Client/ to Resources/Client_backup/
Restart the server
Test connection — if it works, a mod file is corrupted
Add mods back one at a time to find the problem

Client fix:

Deactivate all mods in BeamNG's Mod Manager
Re-enable only MultiplayerBeamMP
Try connecting again

Can't Join Own Server via Browser

Most home routers don't support NAT loopback. Use Direct Connect with 127.0.0.1:30814 instead.

Port Forwarding Not Working

Verify both TCP and UDP are forwarded on port 30814
Check for CGNAT — if your router's WAN IP differs from your public IP (whatsmyip.org), you're behind CGNAT and port forwarding won't work. Use a hosting provider.
VPNs (Hamachi, RadminVPN) are not officially supported and cause UDP issues

Cars Not Moving

Check that the system date and time are correct on the client PC. Incorrect time causes sync failures.