Error Message: Can’t connect to server. Error 12003. An extended error was returned from the server.

This error message is displayed if access to port 443 is blocked.

Our software needs this port open so it can communicate with the server.  Please check with your company’s network engineers that this port is open.

Port 443 is Blocked

Outbound and inbound traffic must be enabled on this port.

If your network administrator does not allow traffic on this port then you can use port 80 instead.  To do this, paste the license link into your browser and change the https to http.  If you have received the license file as an attachment then you need to ask the company that sent you the license file for an HTTP version.
Before you attempt to register again with HTTP, use the ‘Remove Keystore’ option from:

Windows Start menu >> All Programs >> Locklizard >> Safeguard >> Viewer >> Remove Keystore.