config.action_mailer.smtp_settings = {
  address:              'smtp.gmail.com',
  port:                 587,
  domain:               'gmail.com',
  user_name:            'YOUR_USERNAME@gmail.com',
  password:             'YOUR_PASSWORD',
  authentication:       'plain'
  # enable_starttls_auto: true
  # ^ ^ remove this option ^ ^
}