In the screen capture below we have the "Incoming server settings".

Username must be the full e-mail address you are configuring.

Password must be the value assigned to the e-mail address you are configuring.

IMAP Server must be the mail server name associated with the server on which your account is hosted. Please refer to this page to determine which server name to use here.

Under the Security settings, the dropdown contains options for "SSL/TLS" and "STARTTLS", either of which may be used.

Under Authentication another dropdown appears, and that contains options for "NONE" and "CRAM_MD5".

• If your mail client offers "CRAM_MD5", what that will do is to enforce a dual-level of encryption.
  
  
• If you end up using "NONE", that's ok because your e-mail password is still encrypted based on the other settings.

The checkbox labeled "Require sign-in" appears to be the author's implementation of "SMTP Authentication Required". Be sure to select this option, as it is MANDATORY.

Under Authentication another dropdown appears, and that contains options for "AUTOMATIC", ''LOGIN", "PLAIN" and "CRAM_MD5".

• If your mail client offers "CRAM_MD5", what that will do is to enforce a dual-level of encryption.
  
  
• If you end up using "PLAIN", that's ok because your e-mail password is still encrypted based on the other settings.
  
  
• While "AUTOMATIC" works, I cannot locate documentation for that or "LOGIN" in the author's help section.

Now to be fairi, STARTTLS may not work in all cases. On the page where we show you theAndrold (K-9 Mail) configured for POP, that mail APP didn't want to play nice with STARTTLS, so I ended up using SSL/TLS, and that worked fine.