What is the Reason for the Disconnected RDP Connection?

The RDP connection can be dropped due to the following reasons:

  1. Too many simultaneous connections. RDP supports two simultaneous remote connections. Additional connections require Remote Desktop Services CALs (RDS CALs).
  2. Incorrectly configured Group Policy or RDP-TCP properties in the Remote Desktop Services configuration.
  3. Port assignment conflict. For example, another application on the server uses the same port as RDP. The default port for RDP is 3389.
  4. Incorrect configuration of authentication and encryption settings
  5. Damage to the license certificate.

If the RDP connection is broken, the system displays an error message, which may contain information necessary for troubleshooting. More information can be found in the official Microsoft documentation.