Defend - Sending multiple abuse mailbox submission notifications
Incident
Report for KnowBe4
Postmortem
On Tuesday, March 31, 2026, from approximately 15:00 (UTC) to 16:10 (UTC), some users experienced issues with the Defend Abuse Mailbox service.
This incident was caused by a service update that started sending duplicate phishing submission notifications to users. To resolve this issue, we corrected the service update code that caused the duplicate notifications, and the Defend Abuse Mailbox service returned to normal performance by 16:10 (UTC).
To prevent this type of issue in the future, we are reviewing and improving our service upgrade workflow.
No data loss occurred as a result of this issue.
Resolved
This incident has been resolved.
Monitoring
We've implemented a fix and are continuing to monitor to ensure this is resolved
Identified
We've identified some users are receiving multiple abuse mailbox submissions. We've identified a fix which should resolve the issue.
This incident affected: Defend (Mail Flow).