Seeing a high number of complaint alerts from Microsoft? You’re not alone.

This is an industry-wide issue that Microsoft is aware of and is actively working on a resolution, but the fix may take some time. While they have indicated that senders should not see an impact on their reputation, we cannot rule out that some individual senders might see a drop in their inbox placement. 

The issue became initially noticeable on August 11, 2021, where complaints jumped by over 150% overnight and then jumped again in early October. Across all of our SparkPost senders, we have seen the number of complaints increase by over 450% compared to what they were on August 10th.

Chart showing a rise in Microsoft complaints 

We are actively working with Microsoft to more fully understand what the root cause of this issue is and when a resolution will be available. If you are a SparkPost sender and believe your inbox placement has seen a recent hit at Microsoft properties, please open a support ticket. Our deliverability teams can investigate, and, as warranted, open a remediation ticket with Microsoft.

We’ll make updates to this post as we know more. 

~Chris Adams, Distinguished Engineer & Evangelist

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