Email Delivery Issue to Microsoft Office 365


We have monitored the service for stability and this incident shall now be closed.


Between June 9, 2023 at approximately 21:00 UTC and June 11, 2023 at approximately 05:30 UTC, a subset of customers using Microsoft Office 365 service may have experienced incoming emails being flagged as Junk mail. Email delivery remained successful but the mails were incorrectly marked as Junk. As per our initial investigation, this issue appeared to only impact senders using Authenticated Received Chain (ARC). We reached out to Microsoft and reported the issue. We have received confirmation from Microsoft that a fix has been deployed and as of 05:30 UTC, the service is fully operational. Customers should no longer experience emails incorrectly flagged as Junk mail. Any customers still experiencing issues are requested to contact the Broadcom support team.

Please note that there was no impact to protection services, and all other aspects of our services remain functional. We are closely monitoring the email service and will provide updates as soon as new information becomes available.

Began at:

Affected components