If you find that you are receiving 5.1.x errors while trying to send
SMTP emails it may be that your mail server has either the parameter
strict_rfc821_envelopes = yes or adheres strictly to the ESMTP (RFC
5321) protocols which require email addresses to be enclosed in < > as
in "John Doe <jd...@email.com>".
Sendmail allows plain email addresses so you might find this error if
you migrate from a sendmail mailserver to a postfix (or other server).
The Email Component does not currently enclose the addresses in < >
but does use them if they are present in the string that is passed in.
Hope this helps somebody out there before they spend as much time on
the error as I did.
For sake of conventions (and adhering to the RFC), should the email
component format email address strings with the enclosing < > by