---
title: "Microsoft 365 outage: cause, affected services and recovery, Nov. 12–13"
description: "Microsoft says an earlier network-capacity upgrade issue surfaced after a later change. Latest confirmed November 13 recovery status, affected Microsoft 365 features and outage timeline."
date: 2026-11-13T00:00:00.000Z
source: https://venturecapitaltracker.com/microsoft-365-outage-november-2026-services-timeline
---

# Microsoft 365 outage: cause, affected services and recovery, Nov. 12–13

> Microsoft says an earlier network-capacity upgrade issue surfaced after a later change. Latest confirmed November 13 recovery status, affected Microsoft 365 features and outage timeline.

*Latest verified update: 13 November 2026, 17:57 UTC (Microsoft advisory). The incident record was still marked "service degradation" when checked at 19:50 UTC. This article is a reporting snapshot, not a live status dashboard.*

Microsoft says its worldwide Microsoft 365 disruption is **broadly recovering but not yet fully restored**. The company says an issue introduced during an **earlier network-capacity upgrade surfaced after a more recent network change**. Microsoft says the underlying issue has been addressed, while restoration continues for remaining customers and regions. It explicitly says the incident was **not related to cyber activity or AI/agents**. A full post-incident report has not yet been published.

The disruption began on Thursday, 12 November, and continued into Friday, 13 November. Exchange Online mailbox connectivity was the central affected service, with knock-on failures in Microsoft 365 features that depend on email, calendars or related Microsoft services. Microsoft tracked the incident under **EX1550543** (Exchange Online, beginning **16:17 UTC** on November 12) and **MO1550821** (broader Microsoft 365, beginning **18:26 UTC**). [Microsoft's administrator advisories](https://mailservices.isc.upenn.edu/computing/email/penno365/alerts/ms-incidents.html) record both IDs and their updates.

## What is the outage status?

In its **17:57 UTC update on November 13**, Microsoft reported broad recovery and service stability. It said it had corrected the underlying issue and was restoring access gradually to remaining users and regions, validating server stability as demand returned. Both incident records were still classified as **service degradation** in the administrator feed available at 19:50 UTC; Microsoft had not yet declared a complete restoration.

Earlier on November 13, Microsoft reported that email delivery queues had been substantially reduced and were approaching normal levels. It still warned that some users could see intermittent mailbox access problems or delayed delivery. The company had extended its email timeout window to **48 hours** to help preserve delayed messages while queues were processed; this was a mitigation, not a guarantee that every individual message had been delivered.

Independent measurements from [Cisco ThousandEyes](https://www.thousandeyes.com/blog/microsoft-365-outage-analysis-november-12-2026) also showed recovery. At **14:00 UTC**, its monitoring indicated that Outlook availability had largely returned and most monitored users could connect, while some locations continued to show packet loss and timeouts. That observation does not override Microsoft's later incident classification.

## Which Microsoft services were affected?

Microsoft said **features dependent on Exchange Online** could be interrupted; it did **not** report every function of every listed product as unavailable.

| Service | Microsoft-confirmed potential impact | Important distinction |
| --- | --- | --- |
| **Outlook / Exchange Online** | Mailbox connection failures through Outlook on the web, MAPI, Exchange ActiveSync and REST; delayed email delivery; possible hybrid mail-flow disruption | Severity varied by connection method, customer and location |
| **Microsoft Teams** | Calendar access, scheduling, invitations, some channel and contact-management tasks, and Exchange-linked Copilot features | Core meetings, calls, group chat and standard channel messages remained largely functional |
| **Microsoft 365 Copilot** | Copilot Chat loading, responses and access to work mail, calendar or files | This does not establish an outage of unrelated AI models |
| **Microsoft Graph** | Calls involving Exchange mail, calendars and contacts; some Teams administration and activity-notification operations | Microsoft did not report all Graph endpoints as unavailable |
| **SharePoint / Microsoft 365 apps** | Some external file sharing, email-dependent workflows, recent-files views and education features | Direct access to stored SharePoint files remained functional |
| **Defender / Purview** | Some security portals, sensitivity-label processing, DLP workflows, audit searches and eDiscovery actions | Interruption of a portal or workflow does not mean all security protection stopped |
| **Intune / Planner / To Do** | Intermittent device-enrollment or compliance processes and task operations | Impacts were scenario-specific |
| **Power BI / Fabric** | Operations involving sensitivity labels, including some PDF and PowerPoint exports | Not a claim that all reports or Fabric workloads failed |
| **Other Microsoft 365 services** | Selected Microsoft 365 administration, Power Apps mobile sign-in, Universal Print, Viva Engage notifications and Windows 365 Customer Key scenarios | The advisory specified particular features and conditions |

The impact descriptions above follow Microsoft's **MO1550821** notice. They describe services and features that *could* be affected, not a confirmed percentage of customers in each product.

## Timeline: November 12–13, 2026

*All times UTC. Microsoft times are from the administrator service-health notices; the ThousandEyes observations are independently sourced.*

| Time | Confirmed development |
| --- | --- |
| **12 Nov, 16:17** | Microsoft records the start of Exchange Online incident **EX1550543**, affecting several mailbox connection methods. |
| **12 Nov, ~17:30** | ThousandEyes detects Outlook and Microsoft 365 connectivity failures, including connection resets, refused connections and timeouts. |
| **12 Nov, 18:26** | Microsoft opens **MO1550821** for affected Microsoft 365 services and features beyond Exchange. |
| **12 Nov, 19:30–19:43** | Microsoft finds that many servers are unexpectedly unavailable or failing health checks, which shifts traffic to remaining servers. Its earlier assessment of elevated traffic is revised. |
| **12 Nov, 23:59** | Microsoft reports that some restarted servers become unresponsive again once they receive traffic, slowing restoration. |
| **13 Nov, 08:09** | Microsoft reports improved stability after patching an upstream authentication/routing configuration component and expands the change to more infrastructure. |
| **13 Nov, 12:00–14:01** | Microsoft reports improvement in Europe, North America and parts of Asia-Pacific; delayed email queues decline. Residual connectivity and delivery problems remain. |
| **13 Nov, 14:00** | ThousandEyes observes largely restored Outlook availability but continued connection timeouts and packet loss in some locations. |
| **13 Nov, 17:57** | Microsoft identifies the earlier network-capacity upgrade and subsequent network change as the cause sequence disclosed so far, says the underlying issue is addressed and reports broad recovery; final restoration and full post-incident report remain pending. |

## What caused the Microsoft 365 outage?

Microsoft's latest explanation is more specific than the initial reports of unusually heavy load. At **17:57 UTC November 13**, it said a problem introduced during a **previous network capacity upgrade** became apparent after a **subsequent network change**. Microsoft says the underlying issue has been addressed.

The incident advisories document how the problem manifested and why recovery was difficult:

- Some affected servers failed health checks or became unresponsive, reducing available service capacity.
- Traffic was redistributed onto fewer healthy servers; Microsoft later clarified that the high load was **not simply a rise in overall customer traffic**.
- Some restarted servers failed again when traffic returned.
- Engineers tested traffic restrictions, server isolation, an upstream authentication/routing component patch, added capacity and phased restoration.

These are **Microsoft's reported incident observations and mitigation steps**, not an independently verified, complete technical postmortem. Microsoft has promised a post-incident report setting out root-cause details and follow-up safeguards. As of this reporting snapshot, it had not provided that document.

Microsoft explicitly ruled out **cyber activity and AI/agents** as causes. There is also **no established causal link** between this Microsoft 365 incident and separate reports about Azure VM provisioning constraints in European regions. They concern different services and failure scenarios.

## How far did disruption extend?

The affected functions went beyond employee email. [The Associated Press](https://apnews.com/article/microsoft-outage-outlook-email-365-status-down-d92547a821930290db2964388016979a) reported that a court trial in Manchester was interrupted, some UK police forces had problems receiving online crime reports, and institutions in Norway, Greece, Singapore, the Philippines and Japan reported communication or service difficulties. The reported impact differed by organization.

OpenAI and Anthropic also reported problems with **integrations connecting to Microsoft 365 tools**. That is not evidence that their underlying AI models were unavailable.

Downdetector recorded **more than 130,000 US Outlook problem reports near the November 12 peak**, according to contemporary [Reuters reporting](https://interaksyon.philstar.com/trends-spotlights/2026/11/13/321818/microsoft-outage-drags-on-for-hours-disrupting-outlook-teams-for-thousands/). These are user-submitted reports, **not a count of distinct people affected**, and do not establish the total global impact. Microsoft has not released a verified total of affected users for this event.

## What remains unconfirmed?

Microsoft has identified a network-change sequence and reported broad recovery, but has **not yet published a final post-incident report or confirmed full global restoration** in the notices cited here. The exact internal failure chain, complete customer-impact figures and detailed prevention measures are therefore not established in this article.

For the latest status, see [Microsoft's public service-health page](https://status.cloud.microsoft/) or **Health → Service health** in the [Microsoft 365 admin center](https://admin.microsoft.com/#/servicehealth), using incident IDs **EX1550543** and **MO1550821**. The [university-hosted Microsoft notice archive](https://mailservices.isc.upenn.edu/computing/email/penno365/alerts/ms-incidents.html) provides timestamped copies of Microsoft administrator updates.

## Quick answers

**Is Microsoft 365 fully restored?** Not in the last Microsoft advisories checked: the company reported broad recovery but still classified the incidents as service degradation.

**Were Teams calls and chat down for everyone?** No. Microsoft said most core Teams calls, meetings, group chats and standard channel messages remained functional; Exchange-dependent features were affected.

**Were emails lost?** Microsoft confirmed delayed delivery and a 48-hour email timeout mitigation. It did not report that every delayed message had been delivered, nor did it establish a universal loss of email.

**Was this a cyberattack or caused by AI agents?** No. Microsoft explicitly said this was a technical problem unrelated to cyber activity or AI/agents.

**Did this prove an Azure-wide infrastructure shortage?** No. Microsoft identified a problem in the Microsoft 365 service stack involving network changes. No direct connection to separate Azure provisioning-capacity issues has been established.

**By:** [Venture Capital Tracker](https://venturecapitaltracker.com/editorial-policy)
**Last updated:** November 13, 2026

**Editorial note:** AI tools assisted with research, structure, or drafting. Venture Capital Tracker retains human editorial responsibility for factual accuracy, relevance, and source quality before publication.