(BSS/AFP) - Microsoft Outlook suffered a major outage across the world Thursday, with tens of thousands of users struggling to access their email as the company said it was working "aggressively" to reduce the impact.

The disruption, which Microsoft attributed to "elevated load" on its infrastructure, dragged on for much of the US workday and also affected other company products such as Teams and the AI assistant Copilot.

The disruption went global within a span of an hour, knocking out Microsoft products in 74 countries and territories, outage tracker Downdetector reported.

A map posted by Downdetector on X showed the outage affected users across the Americas, and parts of Europe, Asia and Africa.

Microsoft initially said it was investigating outage reports "in the Americas," but later confirmed that the issue apparently affected "Microsoft 365 service connectivity for users in any region."

Microsoft 365 is the company`s cloud-based subscription service that includes popular applications such as Outlook and Teams.

"We`ve determined a portion of infrastructure is experiencing elevated load across multiple regions, which is likely contributing to the connectivity errors," the company wrote on X.

"We`re aggressively pursuing all pathways to reduce impact," it added.

"We`ve paused all deployments, we`re moving additional traffic off the affected infrastructure, and we`re restarting affected servers to return them to service."

In the United States, around 130,000 users reported issues with Outlook shortly after 1 pm Eastern Time (1800 GMT), according to Downdetector.

Outage reports have since declined, with about 37,000 users reporting experiencing issues with Outlook as of 6 pm Eastern Time (2300 GMT).

Thousands of users also reported issues with Teams and Copilot, according to Downdetector.

As the outage dragged on for hours, Microsoft posted a series of updates on X, detailing continued but unsuccessful efforts to restore full service.

In one update shortly after 6 pm Eastern Time, Microsoft said it was "observing limited recovery" as it sought to route user traffic away from affected servers.

"As capacity is restored, users may experience a gradual recovery as their clients reconnect," the company added.