The Advanced section of the ClearSCADA Server Configuration Tool's Global Parameters contains a Server Port setting.
The Server Port setting defines the port number that is used for the server's connection to ClearSCADA. You need to enter the number of an available port.
You can check which ports are currently in use by accessing the Microsoft Windows Command Prompt and entering:
netstat
When you press the Enter key, a list of the TCP ports and the applications that are using them is displayed. You cannot use any of these port numbers—define a different port number for the server port.