I'm trying to align my logo in emails but I'm having trouble with it. Every time I try and send a test email it says: ERROR: Failed sending email to: "xxxxxxxx" [email protected]

This is the code I've tried:


HTML Code:
  <!-- Header Section -->
  <div class="header">
  <img src="http://www.lusttoys.info/email/header.png" alt="logo" align="center"/>
  </div>
Also:

HTML Code:
  <!-- Header Section -->
  <div class="header">
  <img src="http://www.lusttoys.info/email/header.png" alt="logo" align="middle"/>
  </div>
Any ideas? I'm stumped!