I'm running an SMTP server through IIS 6.0 on my Windows 2012 Server, and would like to make delivery of emails to be encrypted.
I have attached an SSL certificate to the server and set Require TLS encryption on the main "Access" page.
I have also enabled the "TLS encryption" checkbox in the "Delivery", "Outbound Security" tab shown here.
.
I'm still getting emails through unencrypted.
What can I do to make delivery of emails encrypted?