Sending, receiving, and organizing email in Outlook.com
Hello
This is related to an outage/incident that's going on today.
Below is the latest update from Microsoft. In this update, Microsoft says they are "progressively" restarting targeted sections of affected infrastructure - so it is entirely possible that you are seeing some accounts already working but some are not. This incident is currently not "cleared" yet.
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Issue ID: EX1464935
Affected services: Exchange Online
Status: Service degradation
Issue type: Incident
Start time: Aug 31, 2026, 10:08 AM CDT
More info
We've confirmed that the authentication component issue impacts other services beyond Exchange Online. For more information regarding other impact scenarios, please see: MO1465074.
We've opted to keep this post (EX1464935) open as Exchange Online remains the most predominantly impacted service.
Users may experience a variety of symptoms related to this event, including but not limited to:
Delays, failures, or incomplete results when searching for content within Exchange Online mailboxes.
Delays or failures when sending or receiving email messages.
Authentication-related errors when accessing Exchange Online services.
Difficulties accessing or performing actions within Exchange administration experiences.
Intermittent failures affecting mailbox operations and message delivery work
Scope of impact
This issue may impact users attempting to send or receive email messages through Exchange Online. We're continuing our investigation to determine the full scope of affected scenarios and will provide additional information as it becomes available.
Preliminary root cause
An issue within a core authentication configuration used by multiple Microsoft 365 services is resulting in impact.
Current status
Aug 31, 2026, 7:01 PM CDT
We're progressively restarting targeted sections of affected infrastructure to ensure the re-applied authentication components are effectively implemented across affected services. We expect this will aid the recovery of affected scenarios. Users should expect delayed delivery of backlogged messages and residual impact across downstream scenarios as these actions are continuing. We'll provide an expected recovery time as soon as one becomes available to us.
Next update by:
Monday, August 31, 2026 at 8:00 PM CDT