Unable to Connect SQL Server through internet

Question

I have configured my SQL Server for remote connection.
I can connect my SQL Server through LAN using my IP address.
But when i try to connect through internet it raise error "A network-related or instance-specific error occurred while establishing connection. The server was not found or was not accessible. Verify that instance name is correct and that SQL Server is configured to allow remote connections."

Please note that my SQL Server is accessible through LAN.
I have set my port opened in Router Port Forwarding Setting.(Port is accessible through internet)

What else should i do for access my SQL Server through internet?

Thanks