EVENT DOSSIER
On August 31, 2026, Microsoft confirmed that its Exchange Online cloud service experienced widespread failures, resulting in delayed email deliveries, failed send attempts, and authentication issues for users. The failure began at 11:30 am on Monday. According to Downdetector statistics, by 2 pm, more than 5,000 users were affected. Preliminary investigations indicated that the problem stemmed from an anomaly in a “authentication component,” which may have been caused by configuration errors, leading to the improper deployment of the component and affecting services other than Exchange. Microsoft has identified the root cause of the problem and is testing some infrastructure to verify the effectiveness of the repair strategy. If the tests are successful, the solution will be implemented globally. Currently, Microsoft is still reviewing recent service changes and continuously optimizing the repair plan.
微软周一确认其 Exchange Online 云服务发生广泛故障，导致 Outlook 用户邮件延迟、发送失败及认证问题。该问题源于一个“认证组件”出现异常，并影响了除 Exchange 外的其他服务。微软已识别出该问题，正对部分基础设施进行测试以验证修复策略的有效性，若成功将全面推广。据 Downdetector 统计，故障自周一上午 11:30 开始，至下午 2 点已有超过 5000 用户报告受影响。微软表示初步调查认为配置错误导致认证组件未能正常部署，目前仍在重新审查近期服务变更并持续优化修复方案。