Here is how the error looks like:
/usr/local/lib/ruby/1.8/net/smtp.rb:930:in `check_response'
/usr/local/lib/ruby/1.8/net/smtp.rb:899:in `getok'
/usr/local/lib/ruby/1.8/net/smtp.rb:828:in `mailfrom'
/usr/local/lib/ruby/1.8/net/smtp.rb:653:in `sendmail'
/usr/local/lib/ruby/gems/1.8/gems/actionmailer-2.3.4/lib/action_mailer/base.rb:684:in `perform_delivery_smtp'
/usr/local/lib/ruby/1.8/net/smtp.rb:526:in `start'
/usr/local/lib/ruby/gems/1.8/gems/actionmailer-2.3.4/lib/action_mailer/base.rb:682:in `perform_delivery_smtp'
/usr/local/lib/ruby/gems/1.8/gems/actionmailer-2.3.4/lib/action_mailer/base.rb:523:in `__send__'
/usr/local/lib/ruby/gems/1.8/gems/actionmailer-2.3.4/lib/action_mailer/base.rb:523:in `deliver!'
/usr/local/lib/ruby/gems/1.8/gems/actionmailer-2.3.4/lib/action_mailer/base.rb:395:in `method_missing'
/usr/local/apache2/Yabe/app/controllers/facebook_controller.rb:381:in `test_smtp'
The way to solve it is very simple.
Please remove <> from the "recipients" and the "from" of your ActionMailer object
