Somewhere in the tutorial it shows how to send a mail to the
sales@example.com account you've created and then at the end when you log in with the
sales@example.com account in the webmail you can see the mail you send, however when I try to send this testmail it just gets returned by the MAILER-DEAMON and when I try to log on in the webmail it also shows an error.
So my issue is why doesn't the mail get delivered to the sales account like in the tutorial?