If your Steam-based game server is running but does not appear in the Steam Server list, port configuration is usually the issue.
Make sure that:
The correct ports are open (Network tab) and assigned to the server (Startup tab)
Query and game ports match the game’s requirements
No other service is using the same ports
After verifying the ports, restart the server and refresh the Steam Server list.
If the issue persists, please submit a ticket.