The "Cannot connect to the Citrix MetaFrame Server. Protocol driver error." Error Message is Displayed when Connecting to a MetaFrame Server

Symptoms

The following error messages that are displayed when connecting to a Citrix MetaFrame server:
If you enable Session Reliability, then the following error message is displayed:
Cannot connect to the Citrix MetaFrame Server. Protocol Driver error.

If you disable Session Reliability, then the following error message is displayed:
Cannot connect to the Citrix MetaFrame Server. The Citrix MetaFrame server you have selected is not accepting connections.

Note: The ICA-TCP and RDP-TCP listeners are enabled on the Citrix MetaFrame server. Additionally, the options to log on to the server are enabled.

You might also observe the following issues:
You are not able to connect to the port 1494, the Independent Computing Architecture (ICA) port, of the server by using the telnet utility.
You are not able to connect to the port 3389, the Remote Desktop Protocol (RDP) port, of the server by using the telnet utility.
When you run the NETSTAT -a command, the output of the command does not display that the server listening on port 1494.
When you run the NETSTAT -a command, the output of the command does not display that the server listening on port 3389.

Resolution

To resolve the issue, complete the following procedure:
Open the Systems Properties dialog box.
Activate the Remote tab.
Select the Allow users to connect remotely to your computer option, as shown in the following screen shot:

Note: You cannot make remote connections to the server, if you do not enable the Allow users to connect remotely to your computer option.