Hello, I'm setting up awsSES on my ispConfig. Under server config I have set up SMTP relay information and under Email rauting I have also set up SMTP. When I send now I get this error: Code: This is the mail system at host mail.zix.is. I'm sorry to have to inform you that your message could not be delivered to one or more recipients. It's attached below. For further assistance, please send mail to postmaster. If you do so, please include this problem report. You can delete your own text from the attached returned message. The mail system <firstname.lastname@example.org>: host email-smtp.eu-west-1.amazonaws.com[126.96.36.199] said: 530 Authentication required (in reply to MAIL FROM command) Reporting-MTA: dns; mail.zix.is X-Postfix-Queue-ID: E51BD1FC51 X-Postfix-Sender: rfc822; email@example.com Arrival-Date: Mon, 12 Jun 2017 18:02:09 +0000 (UTC) Final-Recipient: rfc822; firstname.lastname@example.org Original-Recipient: rfc822;email@example.com Action: failed Status: 5.0.0 Remote-MTA: dns; email-smtp.eu-west-1.amazonaws.com Diagnostic-Code: smtp; 530 Authentication required ForwardedMessage.eml I'm not sure if I should set up zix.is, mail.zix.is or web.zix.is at awsSES for verification. How to fix ?