Symptoms
RDP Connection attempts to a RemoteFX enabled Terminal Server fail, resulting in the following error on the client:
"The remote computer disconnected the session because of an error in the licensing protocol. Please try connecting to the remote computer again or contact your server administrator."
The Terminal Server logs the following event:
Event ID: 1152
Source: TerminalServices-RemoteConnectionManager
Message: The Remote Desktop Virtualization Host server cannot issue a client license. It was unable to issue the license due to a changed (mismatched) client license, insufficient memory, or an internal error.
Cause
This problem occurs when standard RDP security is used by the client to connect to the RemoteFX server.
This can occur under the following conditions:
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The client is a custom application using the Remote Desktop active control. This control uses standard RDP security by default.
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The client is 3rd party or Windows Remote Desktop client that is configured to use standard RDP security. Windows XP SP3 and newer Remote Desktop clients use Enhanced RDP security by default and will not exhibit this problem. Older client operating systems use standard RDP security by default, and will exhibit the symptoms listed in this article.
Resolution
The client must be configured to use Enhanced RDP security.
If the client is a custom application using the Remote Desktop ActiveX control, the client must use minimum control version IMsRdpClientAdvancedSettings4 interface and set the AuthenticationLevel property to either 1 or 2 (default level is 0).
Windows XP SP2 clients running MSTSC.exe can work around this licensing problem by using RDP enhanced security (by selecting the "Attempt authentication" Drop down in the security tab properties of the Remote Desktop Connection client.
