Summary of Impact: Between 09:00 and 12:30 UTC customers may have experienced issues with delayed delivery and/or non-imprinted email due to Office 365 Issues
Root Cause: Transient issues with Exchange Online's SMTP servers meant that O365 was unable to send a subset of email to Exclaimer Cloud between 09:00 and 10:50. Approx. 20% of messages were queued within O365 during this period. Exclaimer processed the backlog of queued messages between 10:50 and 12:30
Mitigation: Microsoft resolved their issue and service was restored. Exclaimer Cloud scaled to meet demand during its busiest periods.
Next Steps: We are working with Microsoft to understand the issue in more detail and if Exclaimer Cloud can be more resilient to these sorts of issues in the future.