I've just updated X-Plane to 11.21r2. The programme asks for my product key, which is auto-populated, but it won't let me press the button to use the key. The only active button is 'I don't have a Product Key'. Is this a bug or has X-Plane invalidated my key? I've wiped the auto-populated number and re-entered the key from my original purchase email but that doesn't work either. Can anyone help?