Microsoft is struggling to fix a major global outage of its service that is reportedly affecting tens of thousands of users.

Services including Teams, Outlook and Microsoft’s artificial intelligence software Copilot have been affected by “connectivity problems”.

“We’re aggressively pursuing all pathways to reduce impact,” the company wrote on X.

Reports of problems with Outlook peaked globally at nearly 140,000 around 18:00 GMT on Thursday, according to monitoring website Downdetector.

The BBC understands there is no indication the outage was caused by a cyber-attack.

The disruption affects programs that are part of Microsoft 365 – a popular online service among businesses that allows them to use workplace tools like Outlook, Teams and OneDrive.

For international organisations, this platform is essential for connecting and collaborating with colleagues around the world.

Among the issues, users may be unable to view certain files or details on their calendar apps, Microsoft said.

Its AI platform, Copilot, may also be unable to work properly.

Messaging and online meetings were largely functional, the firm added.

Microsoft said on X that the outage was caused by a number of servers “being unexpectedly unavailable”, straining its remaining systems.

The company is working to address the issues with its services, said a Microsoft spokesperson.

“We appreciate our customers’ patience while we work to restore services as soon as possible.”

The company later warned that some services that had been restored “can become unresponsive again”, adding that customers “in any region” could be affected.

Users around the world including the US, Japan and Singapore have reported facing disruptions.

AI companies feel the impact

The outage has hit other companies, including AI giants Anthropic and OpenAI, which work with Microsoft’s systems.

ChatGPT-maker OpenAI said it was investigating an issue affecting its connections to Microsoft’s services, which has caused some tools to not work as expected.

Microsoft last month reported an outage of its Azure cloud platform that affected the tech giant’s suite of productivity tools and companies worldwide.

Electric truck maker Workhorse Group, which was expected to report third-quarter results on 12 November, rescheduled it to 16 November, citing business disruptions caused by the global Microsoft outage.