@heckler Hi there, we'll see how we can improve sign ups from these connections, but unfortunately spammers abuse these & we need to make sure that they do not abuse our service.

Details on the court order are explained here: https://np.reddit.com/r/tutanota/comments/k3sfs5/in_englisch_court_forces_mail_provider_tutanota/ge4xywc/ - It is not a backdoor.