Hello,
I hope you are running the Symantec Endpoint Protection Manager and not the Symantec Endpoint Protection Manager Web Console.
Could you try starting the Symantec Endpoint Protection Manager from START >> All Programs >> Symantec Endpoint Protection Manager >> Symantec Endpoint Protection Manager.
NOTE: The Confusion happens since the icon for Symantec Endpoint Protection Manager and Symantec Endpoint Protection Manager Web Console are almost similar.
Secondly, if you are already Symantec Endpoint Protection Manager then try checking the SEPM machine has a static IP address.
Hope that helps!!