Abb OPC Server PGP Freelance

My operator station (OS) 1 has both client & server setup. Similarly operator station(OS) 2 has both client & server.
The OS 1 cannot connect to its server and gives error 'opc server ae' tenore license invalid. Thus no values are displayed.
The OS 1, however can connect to OS 2 Server and values can be displayed.
Any help apperciated.