Either the license server host is not found on the network or an invalid host name is specified.

I am able to connect UFT version 12.52 with the concurrent license server when I am connected with my company's provided vlan network. However, I try to open uft from my home with personal Internet connection, I get below error. It amuses me why license server is not recognisable? 

Error: Either the license server host is not found on the network or an invalid host name is specified.