Email notifications are beating me...

So, I've tried quite a few things, from using my company's internal SMTP server to using an extra gmail account I have and attempting to use their server.  All of it ends up giving me this plugin error:

554 5.7.3 Unable to initialize security subsystem at /usr/lib/ruby/1.8/net/smtp.rb:680:in `check_response'

Here's my current gmail settings.  What am I doing wrong?

 ActionMailer::Base.smtp_settings = {
   :address =>        "smtp.gmail.com",
   :port =>           587,
   :domain =>         "gmail.com",
   :authentication => :plain,
   :user_name =>      "my_user_name",
   :password =>       "my_password"
 }