root bounce

   ----- The following addresses had permanent fatal errors -----
<user@domain.com>
    (reason: 530 Authentication required)
<user@domain.com>
    (reason: 530 Authentication required)

   ----- Transcript of session follows -----
... while talking to email-smtp.us-east-1.amazonaws.com:
>>> AUTH dialogue
<<< 530 Must issue a STARTTLS command first
>>> MAIL From:<user@domain.com> SIZE=543
<<< 530 Authentication required
554 5.0.0 Service unavailable