Microsoft Outlook outage affects over 300 million users worldwide

Microsoft Outlook went down worldwide on Tuesday afternoon, with the outage starting at about 14:30 UTC and affecting the web, desktop and mobile apps. Users across corporate and personal accounts reported being unable to send, receive or even open messages. Microsoft’s own service‑health page confirmed a “major incident” and warned that the problem could last several hours.

Outlook is the centerpiece of Microsoft 365, a suite used by more than 300 million people and countless businesses. When the service falters, companies lose a primary channel for communication, coordination and decision‑making. The timing is especially painful as many offices are gearing up for end‑of‑year reporting and holiday planning, and a prolonged outage can delay projects and cost money. Analysts say the incident highlights how much modern work depends on a single cloud provider.

Within minutes of the failure, users took to social media describing login errors, blank screens and “server not responding” messages. The company’s status dashboard listed a “service disruption” for Outlook, Exchange Online and related services. Microsoft’s official Twitter account acknowledged the issue and said engineers were “actively working on a resolution.” Some IT leaders reported switching to backup email platforms and urging staff to use phone or instant‑messaging tools while the outage persisted. Early estimates from Microsoft suggested the root cause was a hardware fault in an Azure data centre that feeds Outlook’s backend.

Microsoft said the fix is underway and expects full functionality to be restored within the next few hours. The company has promised regular updates on its status page and via Twitter. In the meantime, it recommends that organizations activate any alternate email routes they have set up and keep an eye on official communications. The incident serves as a reminder for businesses to maintain contingency plans for critical cloud services, especially as reliance on digital communication continues to grow.