title: Error when closing pipe to sendmail
body: <p>I am using perl module Mail::Builder::Simple to send email. It using the sendmail utility.
  I get this error when sending the email</p>
  
  <pre><code>error when closing pipe to sendmail:
  
  Trace begun at /usr/local/share/perl5/Email/Sender/Transport/Sendmail.pm line 79
  </code></pre>
  
  <p>I am sure it's some permission issue, but not sure what exact permission is missing. Any idea what I am missing.</p>
  
  <p>I see this error message in the file located at <code>/var/spool/clientmqueue/</code>:</p>
  
  <pre><code>550 5.0.0 Access denied
  554 5.0.0 Service unavailable
  </code></pre>