# SparkPost: Microsoft Mail Delivery Delays and Temporary Rejections

- Impact (vendor’s label): minor
- Status: resolved
- Started: 2026-02-26 17:55 UTC · Resolved: 2026-02-27 17:38 UTC · Duration: 24 h
- Updates: 2 · Affected components: Mailbox Provider Service Interruption
- [Vendor status page: https://stspg.io/lx3fq36y112p](https://stspg.io/lx3fq36y112p)
- [Company: SparkPost](https://rewindex.com/company/sparkpost.md)

## Timeline of updates

- **monitoring** 2026-02-26 17:55 UTC: 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
- **resolved** 2026-02-27 17:38 UTC: Microsoft has confirmed that they made additional changes the night of Thursday, Feb 26th that should have remediated most IP rate limiting and rejection issues.  If you are still seeing impacts, please reach out via your normal support channels and our team can investigate and escalate with Microsoft.


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Canonical: https://rewindex.com/company/sparkpost/incidents/h9dv0txjszz0 · Markdown: https://rewindex.com/company/sparkpost/incidents/h9dv0txjszz0.md · JSON: https://rewindex.com/api/v1/companies/sparkpost/incidents/h9dv0txjszz0 · Generated 2026-10-19T22:28:18.886Z