title: Sporadic error when sending email via AWS SES and CakePHP
body: <p>I have a script written in CakePHP 2.10.18 (running on php 5.6, I know, old stuff). The script is set up to use AWS SES as SMTP server, which most of the time works fine, but every once in a while, <em>without changing the code at all</em>, the sending will fail, providing the following error message: <strong>SMTP server did not accept the password.</strong></p>
  <p>This is the Email configuration in CakePHP:</p>
  <pre><code>public $SMTP_config = array(
              'transport' =&gt; 'Smtp',
              'host' =&gt; 'email-smtp.us-east-1.amazonaws.com',
              'port' =&gt; 587,
              'timeout' =&gt; 30,
              'username' =&gt; 'redacted',
              'password' =&gt; 'redacted',
              'client' =&gt; null,
              'log' =&gt; true,
              'returnPath' =&gt; 'my@email.com',
              'replyTo' =&gt; 'my@email.com',
              'tls' =&gt; true,
              'charset' =&gt; 'utf-8',
              'headerCharset' =&gt; 'utf-8'
      );
  </code></pre>
  <p>The email address used as the from (same as the return path and reply to) is  verified with AWS, everything looks good in the AWS console, DKIM verification ok, the account is in healthy status...</p>
  <p>I can't seem to find what's causing this, any ideas? Why would the password be rejected and then accepted just a few seconds later when I run the script again? Any help would be much appreciated.</p>