https://www.bleepingcomputer.com/news/microsoft/massive-microsoft-365-outage-caused-by-faulty-ecs-deployment/ > 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.