Hi,
been using FF relay without issues for a while,
but found one website where they have the email input in a modal dialog, and this modal dialog has a very high z-index.
So the FF relay dropdown box is only partially visible - behind the websites own popup.
The website: https://www.uzdronusiena.lt/
Click button 'Pasirašyti už', then the popup appears. Then enable first checkbox for the email input to show up.