STARTTLS Cannot be enforced. It will be used automatically if the mail server supports it. The encryption type should be kaş to ‘None/STARTTLS’ in this case. See here for an example on how to configure self signed certificates. DuckDuckGo’s homepage is similar to Google’s, except that there is only one https://numberfields.asu.edu/NumberFields/show_user.php?userid=5994297