Microsoft 365 services, including Outlook and Teams, suffered a global outage lasting over 10 hours, with OpenAI and Anthropic’s Microsoft connectors also affected
The disruption highlights the dependence of businesses and AI platforms on Microsoft’s cloud infrastructure and the cascading impact of outages across connected services
Microsoft traced the outage to server failures and an overwhelmed core process but is yet to confirm a complete restoration despite multiple recovery efforts
A widespread outage at Microsoft brought Outlook, Teams and several other Microsoft 365 applications to a standstill for thousands of users globally on Thursday.
Users faced disruption accessing emails, work files and productivity tools for over 10 hours during the outage.
The disruption also spilled over to third-party platforms, with OpenAI and Anthropic reporting issues with their Microsoft 365 connectors.
As per outage reports on Downdetector, outages in India peaked at 2,162 around 11:44 PM on Thursday (November 12. Reports climbed again to 2,254 around 8:59 AM.
Globally, Downdetector recorded more than 38,000 reports of Microsoft 365 problems and around 4,500 reports related to Microsoft Teams at around 2:07 PM ET on Thursday.
Microsoft initially attributed the disruption to elevated load across its infrastructure in multiple regions. Later, it clarified that the issue was not driven by an increase in traffic but by several servers becoming unexpectedly unavailable, placing additional pressure on the remaining infrastructure.
In an update on X, the company said it had paused all deployments, redirected additional traffic away from the affected infrastructure and begun restoring services.
“We determined the elevated load isn’t driven by an increase in traffic, but by a number of servers being unexpectedly unavailable; straining the remaining infrastructure. We’re working to safely return them to service,” Microsoft said.
Microsoft has been issuing regular updates on X about its efforts to restore services. The company initially said it was testing a configuration change to address a problem that was causing servers to fail automated health checks and become unavailable.
However, the recovery efforts did not provide the expected relief. Microsoft subsequently found that a core process on affected servers was becoming overwhelmed, resulting in capacity loss. It also found that some of the servers that returned to service became unresponsive again upon receiving traffic.
To address the issue, Microsoft began redirecting traffic through alternative routes, temporarily restricting certain types of traffic and adjusting network protocols. It also introduced strategic traffic-blocking measures to improve server stability.
In a subsequent update, the company said these measures had resulted in partial recovery across some regions but had not delivered sustained service restoration. Microsoft said it was exploring alternative approaches to address persistent traffic management imbalances and improve infrastructure stability.
In its latest update on X, posted today, Microsoft said it was pursuing multiple workstreams to reduce the impact of the outage. “We’re engaged in multiple workstreams to alleviate impact, address our current blocker, and returning portions of service infrastructure back to a healthy state. A more comprehensive update can be found at MO1550821 in the Microsoft 365 admin center, as well as if the admin center is not available to you,” the company posted.
What Services Were Affected?
The disruption primarily affected services dependent on Exchange Online, Microsoft’s cloud-based email and messaging platform.
Outlook users faced difficulties accessing their mailboxes through web, desktop and mobile applications. Email delivery was also delayed, while some users reported connectivity issues.
The disruption extended to Microsoft 365 applications, with users experiencing difficulties accessing recently used files. Some pages in the Microsoft 365 admin centre also failed to load.
Microsoft Copilot was among the affected services. Users reported problems loading Copilot Chat and receiving responses through web and desktop applications. Its ability to retrieve work-related information, including emails, calendars and files, was also disrupted.
Microsoft Teams continued to support core messaging and online meetings largely normally. However, features dependent on Exchange Online, including calendars and meeting scheduling, were affected. Some users also reported difficulties creating chats in organisations using Information Barriers.
Other affected services included Microsoft Planner, Microsoft To Do, Microsoft Defender, Microsoft Purview, Microsoft Graph, Microsoft Fabric, Power BI, SharePoint Online, Universal Print and Windows 365.
The outage extended beyond Microsoft’s own applications, affecting third-party services that depend on its infrastructure.
OpenAI said it was investigating an issue with its Microsoft connectors that could prevent new connections from being established and cause certain tools to malfunction.
Anthropic also reported an issue with an upstream provider affecting its Microsoft 365 connector.
The disruption highlighted how outages in widely used cloud infrastructure can have a cascading impact on businesses and services that rely on third-party integrations.
The outage also affected businesses and government organisations that depend on Microsoft’s tech suite.
Microsoft earlier reported an outage affecting its Azure cloud platform in October 2026, which disrupted its productivity software suite and affected businesses across several industries.
The latest update indicates that the recovery process is still ongoing, with the company yet to confirm a complete restoration of affected services.