I want to ensure  that client can communicate with licence service over a proxy sever. Is this possible?  

Cause:  Since proxy servers work as an intermediary server and do not allow for direct communication between clients and servers, proxy servers will not work with the Statistica License Manager service.

Using the licensing service, FLEXlm, with any type of proxy server is not supported.  

The Statistica License Management service, or FLEXlm, uses specific ports for communication.   Please see What ports are used by the Statistica License Manager service?

Related knowledge base articles:  
What files are needed for the FLEXlm vendor daemon used by Statistica
 Error, "The desired vendor daemon is down" in Statistica licensing