Microsoft Outlook (Outlook), an email and calendar application, has reported that its services have gone down globally. The outage has primarily affected Microsoft’s email systems and appears to have been triggered by an update issue, with the company ruling out any indication of a cyber attack.
Microsoft has warned that resolving the problem could take some time, as servers brought back online have become unresponsive again when traffic returns. According to Microsoft’s service health status, the Microsoft 365 outage is affecting a broad range of services, with the most significant disruptions linked to Exchange Online.
It says that users may be unable to access email through Outlook, and email delivery may be delayed. Other impacted services include the Microsoft 365 admin centre and apps, Copilot, Defender, Fabric, Graph, Intune, Planner, Purview, To Do, Power BI, SharePoint Online, Universal Print and Windows 365. Microsoft Teams’ core functions, including calls, meetings, group chats and standard channel messaging, remain largely operational, although features relying on Exchange Online, such as calendar access, scheduling, contact management and some channel functions, are affected.
“As part of our investigation into the sustained traffic management imbalances, we’re reviewing traffic flows and affected infrastructure to identify opportunities to optimize routing. This includes verifying the reasons for service failures so we can develop specific actions to improve stability,” said Microsoft in its recent service health status update. “We’ve monitored the status of the changes applied to improve serviceability and confirmed that change is not taking as expected. We’re identifying alternate workstreams that can be applied to increase capacity in the face of sustained traffic management imbalances.”
In a statement on X, Microsoft365Status (MSFT365Status) said, “We’ve monitored the status of the changes applied to improve serviceability and confirmed they’re not taking as expected. We’re identifying alternate workstreams that can be applied to increase capacity in the face of sustained traffic management imbalances. More info under EX1550543 and MO1550821 in the Microsoft 365 admin center, as well as msft.it/6013xBHsf if the admin center is not available to you.”
Down Detector recorded nearly 130,000 reports of disruptions worldwide, affecting services including Outlook, Word, Excel, PowerPoint, Teams, SharePoint and OneDrive. The outage has also impacted government services, schools using cloud-based administration systems, businesses, the Australian Federal Police and security agencies.
The global Microsoft outage has also affected several major companies, including AI giants Anthropic and OpenAI, both of which rely on Microsoft’s infrastructure. OpenAI, the company behind ChatGPT, was investigating connectivity issues with Microsoft services, which had disrupted the expected functioning of some of its tools. Meanwhile, electric truck manufacturer Workhorse Group postponed the release of its third-quarter results, originally scheduled for 12 November, to 16 November, citing business disruptions caused by the global Microsoft outage as reported by the BBC.
Microsoft has confirmed that its latest service restoration changes have not worked as expected and is investigating alternative ways to increase capacity and manage ongoing traffic imbalances.