You might have came across below given error , when you are connecting to Citrix Presentation Server while launching application.
The issue is with the existing Termincal Server license stored in the user’s machine Registry file.
Just go to the below location and Remove the Registry file and reboot the machine , launch the Citrix Presentation server url and launch the application. Will work. This will regenerate the Terminal Server license keys in the Registry and allow connections.
Now you try to connect/ Launch the Application in Citrix Presentation server , it will connect.