Microsoft Outlook outage cause seemingly revealed

If Outlook wouldn't load for you on Thursday, Microsoft now has a theory about what went wrong. The company said in an X post on Nov. 12 that a component responsible for checking whether its servers are working properly may be behind the failures that took some servers out of service. If Outlook wouldn’t load on Thursday, Microsoft now has a theory about what went wrong. The company said on Nov. 12 the failed health checks "may originate from a specific component on the affected servers" that runs those checks.In its service health update, Microsoft said some servers went offline after failing automated health checks. With parts of its infrastructure under heavier load than usual across multiple regions, the company said that extra strain was likely contributing to connection problems. This Tweet is currently unavailable. It might be loading or has been removed. Microsoft also says it’s "deploying a targeted change to bypass this component on a subset of servers" to see if that brings them back online. It has also taken steps to keep more servers from going out of service. So far, Microsoft says it hasn’t found a recent change that coincided with the start of the outage. The company is still investigating why the checks failed.Microsoft initially flagged trouble accessing Exchange Online mailboxes in the Americas. Exchange Online is the service that stores and delivers email for many Outlook users. The best tech deal this week The Apple iPhone 18 Pro is free right now with T-Mobile Products available for purchase through affiliate links. If you buy something through links on our site, Mashable may earn an affiliate commission. Mashable Light Speed This Tweet is currently unavailable. It might be loading or has been removed. The company later warned that the issue "may affect Microsoft 365 service connectivity for users in any region." Around 1 p.m. ET, nearly 130,000 Outlook problem reports appeared on Downdetector, and users reported trouble loading their inboxes and sending or receiving emails. Copilot users also reported problems. This Tweet is currently unavailable. It might be loading or has been removed. Earlier Thursday, Microsoft had also flagged problems with Teams in North America under incident TM1550488. In a follow-up on X, the company said its automated recovery systems had kicked in and were reducing the disruption. Microsoft is posting updates under EX1550543 and MO1550821 in the Microsoft 365 admin center. If the admin center is also out of reach, Microsoft is directing users to its public service status page. This Tweet is currently unavailable. It might be loading or has been removed. This is a developing story...Want more tech and digital culture news delivered to your inbox daily or sent straight to your device? Sign up for Mashable's Top Stories newsletter or get Mashable push alerts today.