Each newsletter I receive a bunch of the following emails from Amazon:
From: MAILER-DAEMON@amazonses.com Subject: Delivery Status Notification (Failure) An error occurred while trying to deliver the mail to the following recipients: redacted@redacted.com
They often include an attachment. For example, one has the following contents:
Reporting-MTA: dsn; a8-25.smtp-out.amazonses.com
Final-Recipient: rfc822; redacted@redacted.com Action: failed Diagnostic-Code: smtp; 553 5.1.2 Unknown mail server. Could not find a mail server for 307knoxrevords.com Status: 5.1.2
On my last newsletter to about 2.5k subscribers, I got about 20 of these emails.
My guess is this is a notification of a "soft bounce", with my understanding being that Amazon will try again before filing it as a "hard bounce" and giving up. This would explain why in Sendy it reported 0% bounces.
Is this an accurate guess as to what's going on here?