title: Sending Mails with Swiftmailer and Office 365 fails again
body: <p>Trying to send Emails in <strong>Swiftmailer 5.x</strong> via <strong>Office365</strong> </p>
  
  <p>This was working stable for a pretty while:</p>
  
  <pre><code>mailer_transport: smtp
  mailer_host: smtp.office365.com
  mailer_port: 587
  mailer_user: me@mydomain.com
  mailer_password: mypassword
  mailer_encryption: tls
  </code></pre>
  
  <p>and still is the proposed solution in any recent answer/article I found but </p>
  
  <p>this results now in:</p>
  
  <blockquote>
    <p>Uncaught PHP Exception Swift_TransportException: "<strong>Failed to authenticate on SMTP server with username "me@mydomain.com" using 1 possible authenticators"</strong> at .../vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/Esmtp/AuthHandler.php line 181</p>
  </blockquote>
  
  <p>Of course I tripplechecked that username/password are correct and that I can use these credentials in other ways to send mails.</p>