title: Magento 1.6 - Invoice Emails are not being sent
body: <p>I have <code>Magento 1.6.0.0</code> and I use <code>Paypal Express Checkout</code>. The issue is that Invoice emails are not automatically sent. It says at the invoice details page:</p>
  
  <blockquote>
    <p>the invoice email is not sent</p>
  </blockquote>
  
  <p>Can someone tell me whats the issue here? </p>
  
  <p>The Order confirmation emails are sent successfully and I think Paypal data is also getting captured via IPN (or by PDT) as I am getting "Payment Information" filled with data coming from paypal.</p>
  
  <p>Let me know how to get this solved.</p>
  
  <p>Thanks a lot.</p>