DNS over HTTPS (DoH) is a way to encrypt DNS queries and responses between a user's device and the resolving DNS server. For more on this see New in Simple DNS Plus v. 9.0.
To enable this in Firefox, do the following:
Trouble logging in? Simply enter your email address OR username in order to reset your password.
For faster and more reliable delivery, add email@example.com to your trusted senders list in your email software.