Microsoft is currently looking into a significant service disruption that is leading to authentication problems and delays or failures in email delivery for Exchange Online users.
The company first recognized this situation (identified as EX1464935 in the admin center) at 5:30 PM UTC, as it started to investigate a surge of reports from users on social media.
According to the outage monitoring service Downdetector, tens of thousands of Exchange Online users are impacted, facing challenges in receiving emails through Outlook and accessing the Exchange Online platform.
"Microsoft Outlook down" and "Microsoft outage" are even trending on social media.
Microsoft Outlook outage
Microsoft Outlook encountered a potential outage, as per reports from thousands of users on Downdetector.com.
As of 9:06 a.m. PT, over 3,000 users had reported experiencing problems on Downdetector. The majority of users indicated difficulties in receiving messages.
Meanwhile, users are also experiencing connectivity and availability issues related to Microsoft Azure, and there are also circulating reports of problems with Microsoft Teams and the Microsoft Store.
Microsoft has not yet verified the precise connection between these service disruptions.
“We’ve identified an issue with an authentication component which is contributing to impact,” Microsoft 365 Status said in a post on X. “To address this, we’ve developed a remediation strategy, and we’re applying it to a portion of infrastructure to test its efficacy. Once we’ve confirmed this resolves impact, we’ll apply the solution more broadly. For more information, please see EX1464935 in the admin center.”
{{/usCountry}}“We’ve identified an issue with an authentication component which is contributing to impact,” Microsoft 365 Status said in a post on X. “To address this, we’ve developed a remediation strategy, and we’re applying it to a portion of infrastructure to test its efficacy. Once we’ve confirmed this resolves impact, we’ll apply the solution more broadly. For more information, please see EX1464935 in the admin center.”
{{/usCountry}}A significant number of users will experience disruptions via Outlook, as it depends on Exchange Online for accessing mailboxes and delivering emails.
As per Downdetector, 37% of users reporting issues encountered difficulties in receiving messages, 23% experienced problems with the application, and 20% reported challenges with the website.
Microsoft outage symptoms
Microsoft stated that the Outlook outage symptoms include:
Delays or failures in sending or receiving email messages.
Authentication errors when trying to access Exchange Online services.
Challenges in accessing or executing tasks within Exchange administration experiences.
Intermittent failures that affect mailbox operations and message delivery processes.
Microsoft outage cause
Although the company has not disclosed the specific regions affected, it has categorized this outage as an incident, a term generally reserved for critical service issues that significantly impact users.
"We've isolated a common failure pattern across affected Exchange Online requests that is associated with authentication and protocol connectivity," Microsoft said in the latest admin center update.
"We're analyzing service telemetry to identify the underlying source of impact and validate potential remediation options. Additionally, we're continuing to assess the scope of impact and monitor for additional affected scenarios."
Microsoft has tackled several Exchange Online outages in recent months, with the latest occurring in June, when it addressed a significant service disruption that impacted the mail flow pipeline for customers in North America, Asia-Pacific (APAC), and Europe.
In April, the company also rectified Exchange Online mailbox access problems that had sporadically affected Outlook mobile and macOS users for several weeks, as well as an Exchange Online outage that hindered users from accessing their mailboxes through Outlook on the web, Outlook desktop, Exchange ActiveSync, and various other Exchange Online connection protocols.