Did you have trouble accessing Microsoft 365 today? You weren’t alone. According to outage tracker DownDetector, the site was down for thousands of people. At its peak around 9 a.m. ET, more than 24,000 people had reported problems accessing the site. But the site and related Microsoft online services all appear to be back up at this time.

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In response to the outage, a post on X from the Microsoft 365 status account said: “We are investigating an issue where users may be unable to access several Microsoft 365 services. For more details and updates, please visit the Admin Center at MO888473.”

Ironically, Microsoft’s own service health page for its online products and services showed that everything was fine. However, that page mainly refers to consumer products. Another, more enterprise-focused Microsoft status page confirmed that “users may not be able to access one or more Microsoft 365 services.”

Initially, Microsoft stated that the company was reviewing network telemetry, examining any recent changes to its network infrastructure, and working with a third-party Internet service provider to determine the underlying cause.

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In an update to the above-mentioned alert MO888473, Microsoft stated that through working with the ISP, it was able to confirm that a change in the ISP’s managed environment impacted services such as Microsoft Teams, Exchange Online, and SharePoint Online.

After the ISP rolled back the change, the affected sites and services began to recover and are now all back up and running, according to Microsoft’s Service Health Status page for its cloud-based services and the Service Health page for Microsoft 365. In a follow-up post on X, the Microsoft 365 Status account confirmed that the impact had been resolved.

DownDetector initially reported that the issue appeared to be related to problems with Microsoft Azure, the company’s cloud-based environment for businesses and other organizations. The site also reported possible problems with Microsoft services when connecting over AT&T Fiber in the US East region.

Many of the people who responded to Microsoft’s post about X agreed that it appeared to be an issue with AT&T. Some who switched from AT&T to a backup system were then able to access the affected Microsoft services.