title: 554 amazon error code - can't send email
body: <p>When I am trying to send the email via amazon I'm getting the following error:</p>
  
  <pre><code>554 Message rejected: Sending suspended for this account. For more information, please check the inbox of the email address associated with your AWS account.
  </code></pre>
  
  <p>It happened a couple of days ago, with the endpoint <code>eu-west-1</code>. What can be wrong?</p>