From: "Peña, Botp" <botp@...>
Date: 2008-06-21T15:35:41+09:00
Subject: Re: Using actionmailer to send an email

From: APNelson.L [mailto:APNelson.L@gmail.com] 
# ruby mail.rb
# /usr/local/lib/ruby/1.8/net/smtp.rb:680:in `check_response': 530 5.7.0
# Must issue a STARTTLS command first. z80sm1963933pyg.31

this means that the server requires tls.
check the rails list, they know better about actionmailer and its plugins.

kind regards -botp