Exclaimer incident
Delays Routing Emails through Microsoft Exchange Connectors within the US
Exclaimer experienced a minor incident on August 12, 2025 affecting US: Server-Side: Mail Routing - Office 365, lasting 15h 13m. The incident has been resolved; the full update timeline is below.
Affected components
Update timeline
- investigating Aug 12, 2025, 04:48 PM UTC
We are aware of reports that messages are not being delivered or appear in a Pending status when the message status is checked for customers within the US region. At this time, we do not believe the issue to be caused by any configuration or setting issues within Exclaimer itself. You can restore mail flow by temporarily disabling the Mail Flow rule for Exclaimer in your Exchange Online Admin Center. If you have any concerns or require assistance, please do reach out to our Support Team, who will be happy to help.
- monitoring Aug 12, 2025, 07:36 PM UTC
We've been closely monitoring the service for the past hour, and everything appears to be stable. Customers can now begin re-enabling their Exclaimer mail flow rules and resume using the service as normal. We appreciate your patience and understanding. We'll continue to monitor to ensure everything remains stable.
- resolved Aug 13, 2025, 08:02 AM UTC
Microsoft has raised Issue ID EX1133879 for customers in North America, where mail flow may have been delayed by over an hour for the period that we had been monitoring the issue. After continued monitoring, we are confident the primary issue has been resolved. If you had disabled the Mail Flow rules for Exclaimer, then you can look to enable these when possible. If you are continuing to experience issues or have further questions, please don't hesitate to reach out, and we'll be happy to help!