Microsoft Mail Delivery Delays and Temporary Rejections

Incident Report for SparkPost

Monitoring

We are currently seeing elevated temporary rejection rates for email delivered to Outlook.com, Hotmail, and other Microsoft-hosted addresses. Microsoft has acknowledged the issue and is actively investigating. This is a industry-wide issue and not isolated to any specific account. We will continue to monitor and update this page as we receive more information.

Next update: When Microsoft posts a resolution or Bird observes delivery rates normalizing

Posted Feb 26, 2026 - 12:55 EST

This incident affects: Mailbox Provider Service Interruption.