A major Microsoft failure left tens of thousands of users unable to reach Outlook email, Microsoft Teams and the Copilot AI assistant on Thursday, with the company attributing the fault to servers that stopped passing their own automatic health checks.

Reports of Outlook problems on the outage tracker Downdetector climbed to about 130,000 shortly after 1 p.m. US Eastern time, Al Jazeera reported. Some users said mail was neither sending nor arriving; others could not open their inboxes at all.

The figure had fallen to roughly 77,000 by just before 3 p.m., and to about 31,000 by 8 p.m., according to CNN. CNN reports the disruption began shortly after noon and ran through much of the American working day.

What Microsoft said

Microsoft said on X that servers were unavailable and were failing automatic health checks, which put additional load on those still running. It said it was testing a configuration change to redistribute traffic and restarting the affected services.

“We’re working to safely return them to service,” the company said.

In a later update quoted by CNN, Microsoft traced the problem to “failed health checks” that may have originated “from a specific component on the affected servers that’s responsible for processing them,” and said it was restarting servers that “have become unresponsive.” It described itself as “aggressively pursuing all pathways to reduce impact.”

By 8 p.m. the company listed the affected products as those touching Exchange Online and email — Outlook, SharePoint, Teams, Microsoft 365 and Copilot.

How wide was it

The three filings do not describe the same geography, and the difference is worth stating plainly.

Microsoft’s own early notice, as quoted by CNN, referred to users “in the Americas,” and CNN’s headline treats the disruption as a US event. Al Jazeera reports Microsoft as saying the issues “could impact users in any region.” Hiru News described it as a worldwide breakdown affecting tens of thousands, attributing that to foreign media rather than its own reporting.

No filing reached for this report gives a country-by-country breakdown, and none mentions Sri Lanka specifically. Sri Lankan offices running Microsoft 365 would have been in the early hours of Friday morning local time during the worst of it.

Not reported

Microsoft did not say when it expected services to be fully restored, and no filing reports a root cause beyond the failed health checks, a total number of users affected worldwide, or whether any data was lost.