Microsoft says an Azure configuration change caused a major Microsoft 365 outage on Thursday, affecting customers across the Central US region.

This massive outage started around 6:00 PM EST and prevented users from accessing various Microsoft 365 apps and services.

The list of services impacted by the outage includes Microsoft Defender, Intune, Teams, PowerBI, Fabric, OneNote, OneDrive for Business, SharePoint Online, Windows 365, Viva Engage, Microsoft Purview, and the Microsoft 365 admin center.

Xbox Support confirmed that the Xbox Live service was also hit by the issue, saying gamers had problems logging into their accounts.

Throughout the outage, Downdetector has received tens of thousands of service issue reports, with affected Xbox users experiencing server connection issues and saying they couldn’t log in.

After acknowledging the outage, Microsoft said, “We’re working on rerouting the impacted traffic to alternate systems to alleviate the impact more expediently.”

“We’re still observing a positive trend in service availability while we continue to redirect the impacted traffic,” it added two hours later.

In an update to its service health status page and the Azure status history, the company shared that the incident resulted from a buggy configuration change deployed by Azure backend workloads.

“A backend cluster management workflow deployed a configuration change causing backend access to be blocked between a subset of Azure Storage clusters and compute resources in the Central US region,” Redmond explained.

“This resulted in the compute resources automatically restarting when connectivity was lost to virtual disks.”

While the mitigation has been confirmed to be viable, and most affected Microsoft 365 apps and services are now back online, some customers are still experiencing problems accessing and using services like Microsoft Teams and the admin center.

In early July, Xbox Live service was brought down after another major three-hour outage, impacting gamers worldwide and preventing them from signing into their Xbox accounts and playing games.

Microsoft 365 customers experienced other similarly severe outages in January 2023 (caused by a Wide Area Network IP change) and in July 2022 (after a faulty Enterprise Configuration Service (ECS) deployment).