# SparkPost: Incident updated: Microsoft outage: delays delivering to Outlook, Hotmail and Office 365

> Incident updated: Microsoft outage: delays delivering to Outlook, Hotmail and Office 365. Detected 2026-11-13 by Rewindex: what changed on SparkPost’s status page, with the before/after diff.

Canonical: https://rewindex.com/change/reff26e71f2a8e5
Last updated: 2026-11-13T01:13:36Z

**Summary:** _summary pending_
- Kind: Incident update · Label: not classified yet
- Changed: 2026-11-13 01:13 UTC · Detected: 2026-11-13 01:13 UTC
- [Source: https://status.sparkpost.com/incidents/37r4xk532jd6](https://status.sparkpost.com/incidents/37r4xk532jd6)
- [Company: SparkPost](https://rewindex.com/company/sparkpost.md)
- Versions: before incident\_version:755/37r4xk532jd6@3af45d678700 → after incident\_version:755/37r4xk532jd6@3895f0075014
- Change 4 of 6 for this incident

Incident page (full timeline): [Microsoft outage: delays delivering to Outlook, Hotmail and Office 365](https://rewindex.com/company/sparkpost/incidents/37r4xk532jd6.md)
## What changed

**1. Added: Update** (identified) · 2026-11-13 01:11 UTC

```diff
+ Microsoft has identified a likely cause of incident EX1550543. A process on its servers that establishes secure connections is becoming overwhelmed, which stops the servers from handling requests. Microsoft has started rolling back a recent network configuration change that coincides with the start of the problem. It is also testing a fix that it plans to apply across all affected servers. Microsoft expects to post its next update by 02:00 UTC, and you can follow it at https://status.cloud.microsoft/m365/referrer=serviceStatusRedirect. Delivery to Outlook.com, Hotmail, Live, MSN and Office 365 recipients is still heavily delayed. More mail is getting through than earlier this evening, but most delivery attempts to Microsoft are still being deferred, and we have not yet seen the effect of Microsoft's changes. SparkPost's systems are working normally. Messages still waiting for Microsoft are queued and retried automatically, so please don't resend them, because that would create duplicates once they are delivered. Because the problem has now lasted more than seven hours, messages with an expiration time of up to several hours may expire before Microsoft accepts them. Each expired message generates a bounce event, and since expired messages are no longer queued, you can decide whether to resend those specific messages.
```

## History of this incident

| When (UTC) | Change | Label |
| --- | --- | --- |
| 2026-11-12 21:43 UTC | [Incident updated: Microsoft outage: delays delivering to Outlook, Hotmail and Office 365](https://rewindex.com/change/r7506228251f9a0.md) |  |
| 2026-11-12 22:33 UTC | [Incident updated: Microsoft outage: delays delivering to Outlook, Hotmail and Office 365](https://rewindex.com/change/r403c7e39cf13b3.md) |  |
| 2026-11-13 00:03 UTC | [Incident updated: Microsoft outage: delays delivering to Outlook, Hotmail and Office 365](https://rewindex.com/change/rb58b9a0cad2e69.md) |  |
| 2026-11-13 01:13 UTC | Incident updated: Microsoft outage: delays delivering to Outlook, Hotmail and Office 365 (this change) |  |
| 2026-11-13 03:13 UTC | [Incident updated: Microsoft outage: delays delivering to Outlook, Hotmail and Office 365](https://rewindex.com/change/r76cb3ac7c22169.md) |  |
| 2026-11-13 03:23 UTC | [Incident updated: Microsoft outage: delays delivering to Outlook, Hotmail and Office 365](https://rewindex.com/change/r4c3527cb8810d5.md) |  |

Previous: [change](https://rewindex.com/change/rb58b9a0cad2e69.md) · Next: [change](https://rewindex.com/change/r76cb3ac7c22169.md) · All SparkPost changes: [timeline](https://rewindex.com/company/sparkpost/changes.md)
_Diff excerpts are shown on normalized text: dates, counters and tokens appear as ‹date›, ‹count›, ‹tok›; noise-only edits are hidden. Rewindex shows the changed passages, not a copy of the page._

## Cite this

Incident updated: Microsoft outage: delays delivering to Outlook, Hotmail and Office 365 on SparkPost’s status page, changed 2026-11-13 01:13 UTC (change 4 of 6).

- Canonical URL: https://rewindex.com/change/reff26e71f2a8e5
- Citation: SparkPost, “Incident updated: Microsoft outage: delays delivering to Outlook, Hotmail and Office 365” (2026-11-13 01:13 UTC). Archived by Rewindex: https://rewindex.com/change/reff26e71f2a8e5 (CC BY 4.0).
- Markdown link: `[SparkPost: Incident updated: Microsoft outage: delays delivering to Outlook, Hotmail and Office 365 (2026-11-13)](https://rewindex.com/change/reff26e71f2a8e5)`


---
Canonical: https://rewindex.com/change/reff26e71f2a8e5 · Markdown: https://rewindex.com/change/reff26e71f2a8e5.md · JSON: https://rewindex.com/api/v1/changes/reff26e71f2a8e5 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-11-13T04:08:01.226Z