Your Discover & Go pass can only be printed by using the green "Print/Download" button within your Discover & Go account:
You cannot print from your browser's print option, nor from the "Ctrl+P" keyboard shortcut.
NOTE: You cannot cancel your reservation once the "Print/Download" button has been clicked. We recommend not printing your pass until right before you visit the attraction. That way, you can cancel if necessary.
Here is further information on printing and cancelling: https://youtu.be/DT8ayGjefAU