Status Page

2026-03-16	Status	Description
02:18 PM		Service Restored Title: Some users may have experienced issues when accessing their Exchange Online mailbox via one or more connection method User impact: Users may have experienced errors when accessing their mailbox via multiple Exchange Online connection methods. More info: Users may have experienced errors or failures when attempting to access their mailbox. Impacted connection methods included, but were not limited to: - Outlook on the web - Outlook desktop - Exchange ActiveSync - Other Exchange Online connection protocols Final status: We've confirmed that service has remained healthy for an extended period of time. Our monitoring indicates the issue is no longer occurring for the affected users. Scope of impact: Impact was specific to some users attempting to access their mailbox via any of the connection methods detailed above. Start time: Monday, March 16, 2026, at 9:30 AM UTC End time: Monday, March 16, 2026, at 1:30 PM UTC Preliminary root cause: An underlying issue involving the supporting network infrastructure resulted in a service availability degradation across the Exchange Online connection methods. We're continuing to investigate to determine the full root cause and will provide more information within the Post-Incident Report. Next steps: - We're continuing to examine the underlying circumstances that led to this behavior to understand the root cause. We'll provide a preliminary Post-Incident Report within two business days and a final Post-Incident Report within five business days.
11:58 AM		Title: Some users may be unable to access Office.com or the Microsoft 365 Copilot web sign‑in page User impact: Users may be unable to access Office.com or the Microsoft 365 Copilot web sign‑in page. More info: The impacted Microsoft 365 Copilot web-clients are office.com/chat and m365.cloud.microsoft/chat. Users can access Microsoft Copilot through application-based Microsoft Copilot services. This includes, but is not limited to: - Microsoft Copilot desktop app - Copilot in Microsoft Teams - Copilot in Office apps Current status: We've identified that a section of service infrastructure is not processing traffic efficiently. We're making configuration changes to remediate impact. Scope of impact:: Impact is specific to some users who are served through the affected infrastructure. Next update by: Monday, March 16, 2026, at 4:30 PM UTC
11:18 AM		Title: Some users may experience issues when accessing their Exchange Online mailbox via one or more connection method User impact: Users may experience errors or failures when accessing their mailbox via one or more Exchange Online connection methods. More info: Users may experience errors or failures when attempting to accessing their mailbox. Impacted connection methods include but may not be limited to: - Outlook on the web Current status: We’ve identified a backend issue that’s preventing some services from responding as expected, resulting in mailbox access delays. We’re investigating this behavior across regions to better understand the impact and determine next steps. We’re seeing signs of service recovery and will share additional updates as our investigation continues. Scope of impact: Impact is specific to some users attempting to access their mailbox via any of the connection methods detailed above. Next update by: Monday, March 16, 2026, at 3:30 PM UTC
08:56 AM		Title: Users may be unable to create or edit Ownerless Groups policies in Exchange Online User impact: Users may be unable to create or edit Ownerless Groups policies in Exchange Online. Final status: We’ve successfully developed and deployed the fix and after our validations have confirmed that impact is resolved. Scope of impact: Users attempting to create or update Ownerless Groups policies in Exchange Online were impacted. Start time: Thursday, February 12, 2026, at 3:33 PM UTC End time: Monday, March 16, 2026, at 6:30 AM UTC Root cause: A recent update to the authentication flow is caused the call to DSAPI to update Ownerless Groups policies to fail due to outdated authentication flow mapping, resulting in the impact. Next steps: - We're reviewing our update procedures to better identify similar issues during our development and testing cycles This is the final update for this event.

02:18 PM

Service Restored

Title: Some users may have experienced issues when accessing their Exchange Online mailbox via one or more connection method
User impact: Users may have experienced errors when accessing their mailbox via multiple Exchange Online connection methods.
More info: Users may have experienced errors or failures when attempting to access their mailbox. Impacted connection methods included, but were not limited to:
- Outlook on the web
- Outlook desktop
- Exchange ActiveSync
- Other Exchange Online connection protocols
Final status: We've confirmed that service has remained healthy for an extended period of time. Our monitoring indicates the issue is no longer occurring for the affected users.
Scope of impact: Impact was specific to some users attempting to access their mailbox via any of the connection methods detailed above.
Start time: Monday, March 16, 2026, at 9:30 AM UTC
End time: Monday, March 16, 2026, at 1:30 PM UTC
Preliminary root cause: An underlying issue involving the supporting network infrastructure resulted in a service availability degradation across the Exchange Online connection methods. We're continuing to investigate to determine the full root cause and will provide more information within the Post-Incident Report.
Next steps:
- We're continuing to examine the underlying circumstances that led to this behavior to understand the root cause.
We'll provide a preliminary Post-Incident Report within two business days and a final Post-Incident Report within five business days.

11:58 AM

Title: Some users may be unable to access Office.com or the Microsoft 365 Copilot web sign‑in page
User impact: Users may be unable to access Office.com or the Microsoft 365 Copilot web sign‑in page.
More info: The impacted Microsoft 365 Copilot web-clients are office.com/chat and m365.cloud.microsoft/chat.
Users can access Microsoft Copilot through application-based Microsoft Copilot services. This includes, but is not limited to:
- Microsoft Copilot desktop app
- Copilot in Microsoft Teams
- Copilot in Office apps
Current status: We've identified that a section of service infrastructure is not processing traffic efficiently. We're making configuration changes to remediate impact.
Scope of impact:: Impact is specific to some users who are served through the affected infrastructure.
Next update by: Monday, March 16, 2026, at 4:30 PM UTC

11:18 AM

Title: Some users may experience issues when accessing their Exchange Online mailbox via one or more connection method
User impact: Users may experience errors or failures when accessing their mailbox via one or more Exchange Online connection methods.
More info: Users may experience errors or failures when attempting to accessing their mailbox.
Impacted connection methods include but may not be limited to:
- Outlook on the web
Current status: We’ve identified a backend issue that’s preventing some services from responding as expected, resulting in mailbox access delays. We’re investigating this behavior across regions to better understand the impact and determine next steps. We’re seeing signs of service recovery and will share additional updates as our investigation continues.
Scope of impact: Impact is specific to some users attempting to access their mailbox via any of the connection methods detailed above.
Next update by: Monday, March 16, 2026, at 3:30 PM UTC

08:56 AM

Title: Users may be unable to create or edit Ownerless Groups policies in Exchange Online
User impact: Users may be unable to create or edit Ownerless Groups policies in Exchange Online.
Final status: We’ve successfully developed and deployed the fix and after our validations have confirmed that impact is resolved.
Scope of impact: Users attempting to create or update Ownerless Groups policies in Exchange Online were impacted.
Start time: Thursday, February 12, 2026, at 3:33 PM UTC
End time: Monday, March 16, 2026, at 6:30 AM UTC
Root cause: A recent update to the authentication flow is caused the call to DSAPI to update Ownerless Groups policies to fail due to outdated authentication flow mapping, resulting in the impact.
Next steps:
- We're reviewing our update procedures to better identify similar issues during our development and testing cycles
This is the final update for this event.