When you send an email to someone that bounces back, the server that bounced it typically includes an server mail transfer protocol (SMTP) reply that explains why the message bounced. You can view this information in your campaign report for up to 30 days after you've sent your campaign.
In this article, you'll learn about SMTP replies and how to view bounce reasons in your campaign report.
Understanding bounces and SMTP replies
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 Bounce Reason to view the SMTP reply.
We log any bounces for a campaign in the campaign report. Bounce reasons are stored in the account for 30 days. Bounce reasons must be viewed individually for each bounce on a campaign, and it's not possible to export a full list of all the bounce reasons for a campaign. 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 these steps.