Duplicate incidents created by pagerduty when using email integration

Hey there! 👋

Thanks for the details.

That pattern usually means PagerDuty is actually receiving more emails than the one you sent, most often because of an email loop. For example:

• PagerDuty sends a notification email about the incident
• That email ends up back at the integration’s email address (through a reply-all, a forwarding rule, or a distribution list that includes the integration address)
• PagerDuty treats it as a new email and creates another incident, and the cycle repeats

Since the service has worked for two years and this only started recently, it’s worth checking whether anything changed on the email side, like a new forwarding rule or the integration address being added to a group list.

How to check: open two of the duplicate incidents, click View Message, then View Raw Message. Compare the sender and subject. If the duplicates come from PagerDuty or from a mailing list rather than your monitoring tool, you’ve found the loop.

How to fix it:

1. Remove the loop at the source, for example by taking the integration address off any lists or forwarding rules.
2. Add an email filter on the integration so it only accepts emails from your monitoring tool’s sender address.
3. If replies and forwards are the cause, the troubleshooting guide has a rule you can set up so “RE:” and “FWD:” emails get added to the existing incident instead of creating new ones.

To stop the duplicates while you investigate: in the integration’s Email Management settings, you can switch to Open a new incident/alert only if an open incident does not already exist. That way only one incident can be open at a time, and any extra emails get added to it.

It’s also worth checking what that setting was before. The default groups emails with the same subject line, but if it’s set to open a new incident for every email, or if your subject line changes slightly each time (a timestamp, for example), duplicates can slip through.

Helpful docs:

• Email Integration Troubleshooting Guide
• Email Management: Filters and Rules

If you’re still seeing duplicates after checking these, let us know what the raw messages show (with anything sensitive removed) and we’ll dig in further!