title: Sender address rejected error while sending emails
body: <p>I am developing a ruby on rails application which sends out emails. When I try to send emails from mailer is says <code>553 : Sender address rejected: not owned by user X</code>. 
  But I try to send an email manually using <code>Net::SMTP</code> it goes well. I am kind of stuck for the release. Please help!!!</p>