Read SMTP Replies for Bounces

When you send an email to someone that bounces back, the server that bounced it typically includes an "SMTP Reply" that explains why the message bounced. Find that information in the header of the bounced message.

Understanding bounces

When MailChimp gets a bounced message, we try to read its SMTP reply and categorize the email as a "soft" or "hard" bounce for you. However, some email servers don't send bounces with properly formatted SMTP replies that use standard codes. In those cases, MailChimp has to make an educated guess as to how to categorize that bounced message. If you want to know specifically why a message bounced, or if you feel MailChimp categorized a bounce improperly, read its SMTP reply.

We also factor subscriber engagement activity into our bounce cleaning decisions.

Viewing bounce reasons

We log any bounces for a campaign in the campaign report. Bounce information and headers are stored for 30 days. It's important that you check your bounces right away to ensure no valid emails bounced, that there were no syntax errors, and that you've manually cleaned your internal database if you need to.

To view the bounce reasons for a campaign follow the steps below.

  1. Navigate to the Reports page.
  2. Click the View report button for the campaign.
  3. Click the link for the number of Bounced emails for this campaign.

    row of data, including the number of bounces, which is a link to more information.

The Bounced page of the campaign report shows all bounced email addresses for a campaign and next to each email address we'll note whether the bounce was hard or soft.

To view the bounce reason for each email address click the Bounce Reason link at the end of each subscriber row. You may have to scroll to the right to see the link if you have a lot of fields in your list.

After clicking the Bounce Reason link, a report for the address opens in a separate browser tab detailing what caused the email to bounce.
subscriber activity, bounces

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