If you see a "License Invalid" error message when attempting to login to your WHMCS admin area this means you are accessing your installation from an unlicensed location. Your WHMCS licence is tied to a specific IP address, folder and domain, so if any of these have changed you will see this error message.
To remove this error message please Create a Ticket to the WHMCS department using the link on the right menu. We will then reissue the licence to the new location, no changes are necessary at your end.