Microsoft says it has started to restore access to its Teams communications app after a major outage left users unable to access it and other Microsoft 365 products for several hours.

Microsoft Teams suffered an outage
Teams has been down for many users overnight (Pic: Wachiwit/iStock)

The app was apparently unavailable for thousands of users overnight, with more than 4,500 people registering a problem on Down Detector, a service which logs outages of popular services.

Teams down: why was Microsoft chat app unavailable?

The incident was acknowledged by Microsoft at 2.47am, and the company later tweeted: “We’ve determined that a recent deployment contained a broken connection to an internal storage service, which has resulted in impact. We’re working to direct traffic to a healthy service to mitigate impact.”

Other services have also been impacted, Microsoft said: “We’ve identified downstream impact to multiple Microsoft 365 services with Teams integration, such as Microsoft Word, Office Online and SharePoint Online,” it added in a later tweet.

Engineers have been working to fix the problem, and services are now beginning to be restored. However, businesses could still experience disruptions this morning.

Teams outage and the reliance on cloud-based infrastructure

Teams became popular with businesses during the Covid-19 pandemic and the widespread switch to remote working. Despite competition from rivals such as Zoom, it has become one of the most popular communications apps, thanks in part to its inclusion in the Office 365 productivity suite. Microsoft said in its most recent earnings call that Teams has 270m active users.

The incident highlights the huge impact an outage of cloud services can have on businesses. Such outages are rare for Big Tech firms, but a similar incident struck Meta, Facebook’s parent company, in November, when a DNS issue took down Facebook, as well as Instagram and WhatsApp, for more than six hours.

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