Duplicate emails in automation campaigns can confuse recipients and harm your brand’s professionalism. Explore the common causes, preventive steps, and troubleshooting methods that help your campaigns run smoothly and reliably.
Before you start
Make sure you have:
An understanding of your campaign workflow and recipient criteria.
Common causes of duplicate emails
Duplicate emails typically happen when automation triggers or rules overlap. Common reasons include:
Overlapping join actions in lists
When two or more join actions in a contact list trigger email sends at the same time, recipients may get duplicates.
Example:
One join action sends a campaign immediately.
Another join action enrols the contact into a program that sends the same campaign again.
Multiple program enrolments
Contacts can meet the criteria for multiple automation programs that use the same or similar campaigns. Each program sends its own version, which looks like a duplicate.
Incorrect exclusion rules
If exclusion rules are configured for the wrong or outdated campaign, contacts may bypass restrictions and receive duplicate sends. This often happens when campaigns have similar names, making it easy to select the wrong one when setting the rule.
Prevent sending duplicate emails
To reduce the risk of duplicate sends, review your automation setup and make targeted adjustments to triggers, enrolment criteria, and limits.
Streamline join actions
Update the join actions for your contact lists to avoid duplicate triggers. You can:In Dotdigital, go to Audience > Lists, select Propeties of your list and remove secondary Program enrollment.
In the same view, disable List-based triggers that overlap with automation programs.
Learn more in Send contacts a campaign or enrol them on a program when they join a list.
Set clear enrolment rules
Ensure each automation program has distinct criteria so contacts only join the intended program and aren’t enrolled in multiple programs unnecessarily.
Review enrolment limits
Regularly check that enrolment limits prevent contacts from rejoining a program too soon.
Use the campaign ID or unique identifier to confirm send history.
Cross-check enrolment behaviour against a contact’s Activity timeline.
Learn more in Understand and create program start conditions.