A bounce is an email whose delivery was rejected by the recipient email server. The reason an email is rejected for delivery determines if that bounce is considered hard or soft. MailChimp logs all bounces for each campaign as part of the campaign report. In this article we explain the difference between hard and soft bounces and how to view bounce reasons for a campaign.

Contents

Bounce types

Hard Bounces

A hard bounce indicates a permanent reason an email cannot be delivered. Hard bounced email addresses are removed automatically and immediately from the active subscribers and placed in the Cleaned portion of your list. Cleaned subscribers will be excluded from future campaign sends to this list. While there are many reasons an email address may hard bounce, below are some common reasons this could happen.

  • Recipient email address does not exist
  • Domain name does not exist
  • Recipient email server has completely blocked delivery

Soft Bounces

Soft bounces typically indicate a temporary delivery issue to an address and are handled differently than hard bounces by MailChimp. When an email address soft bounces it means delivery to that address was attempted multiple times over the course of 3 days, but was not successful. After attempting delivery for those 3 days, we log the email address as a soft bounce on the campaign report. If that email address continues to soft bounce on subsequent campaigns, the address will eventually be considered a hard bounce and cleaned from your list. We'll allow 7 soft bounces for an email address with no subscriber activity and up to 15 soft bounces for subscribers with previous subscriber activity before converting a soft bounce into a hard bounce. While there are many reasons an email address may soft bounce, below are some common reasons this could happen.

  • Mailbox is full (over quota)
  • Recipient email server is down or offline
  • Email message is too large

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.

    Number of bounces

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

Notes

  • If a valid email address bounced for a campaign, take a look at this article for some reasons why this may have happened.
  • If you see a high number of bounces and your From email address is at AOL or Yahoo, it is likely that the delivery of your campaign was affected by changes in DMARC policies.
  • Exporting bounce reasons is currently not an option in MailChimp. When you view a bounce reason you're looking at an individual text file for each bounce and exporting multiple text bounce files at once would cause performance issues in MailChimp. The best thing to do for now is to view them directly in the account. If you'd like to download the list of bounced addresses for a campaign take a look at this article.

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