Microsoft 365 hit by major outage, thousands report service disruptions

It was mid-afternoon when users across the U.S. suddenly found they couldn’t log into Microsoft 365. The disruption wasn’t subtle — Downdetector recorded over 16,200 reports of issues around 2:33 p.m. ET on Thursday, according to a report from Reuters.

Microsoft confirmed on its status page via X that it was investigating trouble with access to multiple services. At that point, the scale of impact and root cause were still unknown.

Outages of this size aren’t unheard of for Microsoft 365 these days. Earlier this year, a flawed code change led to a weekend outage that affected Outlook, Teams, and Exchange. Microsoft rolled back the change and restored service after many users had already been impacted. In another event, a misconfigured traffic-management update triggered widespread failures across Teams and Exchange.

“There were nearly 17,000 incidents of people reporting issues with Microsoft 365 as of 2:39 p.m. ET, according to Downdetector, which tracks outages by collating status reports from a number of sources, including user-submitted errors on its platform,” Reuters reported.

Those past incidents hint at how fragile large cloud systems can be — a tiny misstep in networking or routing logic can cascade into a mass outage. Some expert post-mortems have pointed to Azure Active Directory (now Entra ID) or misrouted traffic via Azure Front Door as frequent bottlenecks.

By Thursday afternoon, users were already reporting irregular behavior: network timeouts, login failures, and missing responses from collaborative apps. Microsoft had to scramble, rerouting traffic and monitoring telemetry for signs of recovery.

At press time, Microsoft had not released a detailed breakdown of the failure, but its response was underway. Given Microsoft’s size and reach, any outage of this magnitude ripples across businesses, educational institutions, and individuals who depend on cloud productivity tools daily.

I’ll keep an eye on further updates and share what we learn about why this happened — and whether Microsoft is doing anything to prevent the next one.