A. The Microsoft Clearinghouse, which authorizes Terminal Services License servers, has made a change to the certificates that the clearinghouse provides to terminal servers that can result in the following error when an XP client attempts to connect to the Win2K Terminal Services server:

Because of a security error, the client could not connect to the terminal server. After making sure that you are logged on to the network, try connecting to the server again.

XP clients have a built-in Client Access License (CAL) for accessing Win2K Terminal Services servers. To resolve the error, you need to delete the XP Terminal Services License information from the registry and modify the Certificate types on the Win2K Terminal Services server. On the Win2K Terminal Services server, perform the following steps:

  1. Start a registry editor (e.g., regedit.exe).
  2. Navigate to the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TermService\Parameters subkey.
  3. Delete the Certificate, X 509 Certificate, and X 509 Certificate ID values.
  4. Close the registry editor, then restart the server.

On the XP client, perform the following steps:

  1. Start a registry editor (e.g., regedit.exe).
  2. Navigate to the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft subkey.
  3. Delete the MSLicensing subkey.
  4. Close the registry editor.
  5. Connect to the terminal server.

If performing these steps doesn't resolve your problem, you need to contact the Microsoft Clearinghouse to deactivate and reactivate your Win2K Terminal Services Licensing server.