Massive Microsoft 365 outage caused by faulty ECS deployment
By Sergiu Gatlan, Bleeping Computer In a preliminary post-incident report, Microsoft has revealed that this week's 5-hour-long Microsoft 365 worldwide outage was triggered by a faulty Enterprise Configuration Service (ECS) deployment that led to cascading failures and availability impact across multiple regions. ECS is an internal central configuration repository designed to enable Microsoft services to make wide-scope dynamic changes across multiple services and features, as well as targeted ones such as specific configurations per tenant or user. What initially started like a minor Microsoft Teams outage ended up expanding downstream to multiple Microsoft 365 services with Teams integration that also leverage ECS, including Exchange Online, Windows 365, and Office Online. As a result, users worldwide began reporting that they could not use Microsoft Teams and multiple Microsoft 365 services or features. "This issue affected the users' ability to connect to the Microsoft...