Status Page

2026-04-01	Status	Description
03:24 PM		Service Restored User impact: Users may have been intermittently unable to access their Exchange Online mailboxes in some connection methods. More info: This issue may have intermittently impacted some users who attempted to access the Exchange Online service through the Outlook mobile apps or the new Outlook for Mac desktop client. Final status: We've monitored the service for an extended period of time and confirmed that error counts have remained below pre-incident levels, confirming remediation.
01:31 PM		Service Degradation Title: Some users may be unable to access their mailboxes through multiple connection methods in Exchange Online User impact: Users may be unable to access their mailboxes through multiple connection methods in Exchange Online.
08:43 AM		Title: Some users may be unable to access custom add-ins through any Exchange Online connection method User impact: Users may have been unable to access custom add-ins through any Exchange Online connection method. More info: For additional guidance on managing Exchange Web Services, please refer to the following: https://learn.microsoft.com/en-us/exchange/client-developer/exchange-web-services/how-to-control-access-to-ews-in-exchange Final status: We’ve identified that a recent Exchange Web Services (EWS) deprecation update and an Exchange Online authentication change prevented users from accessing custom add-ins in Outlook. To remediate this issue, we rolled back both offending changes and verified through service monitoring that this action successfully resolved the impact. Admins that have disabled EWS may continue to experience this issue and we recommend that admins re-enable EWS at this time. For additional guidance on managing Exchange Web Services, please refer to the following: https://learn.microsoft.com/en-us/exchange/client-developer/exchange-web-services/how-to-control-access-to-ews-in-exchange Scope of impact: Some users who are attempted to access custom add-ins through all Exchange Online connection methods may have been impacted. Start time: Thursday, March 12, 2026, at 10:04 PM UTC End time: Friday, March 27, 2026, at 1:40 AM UTC Root cause: A recent EWS deprecation update and an Exchange Online authentication change prevented users from accessing custom add-ins in Outlook. This is the final update for the event.
08:42 AM		Title: Some users may be unable to access the default add-ins in Outlook User impact: Users may have been unable to access the default add-ins in Outlook. More info: This issue impacted both the Outlook desktop client and Outlook on the web. Some affected users found that the “My Templates” icon was missing from the Outlook ribbon, and others were unable to find templates in the AppData Microsoft Templates location, even though templates were known to exist and were still being used by non-impacted users. Some users also reported that the Viva Insights add-in was impacted by this event. Final status: We’ve identified that a recent Exchange Web Services (EWS) deprecation update and an Exchange Online authentication change prevented users from accessing default add-ins in Outlook. To remediate this issue, we rolled back both offending changes and verified through service monitoring that this action successfully resolved the impact. Admins that have disabled EWS may continue to experience this issue and we recommend that admins re-enable EWS at this time. For additional guidance on managing Exchange Web Services, please refer to the following: https://learn.microsoft.com/en-us/exchange/client-developer/exchange-web-services/how-to-control-access-to-ews-in-exchange Scope of impact: Some users attempting to access or use the default add-ins within Outlook may have been impacted. Start time: Thursday, March 12, 2026, at 10:04 PM UTC End time: Friday, March 27, 2026, at 1:40 AM UTC Root cause: A recent EWS deprecation update and an Exchange Online authentication change prevented users from accessing default add-ins in Outlook. Next steps: - We’re reviewing how the impacting changes prevented users from accessing default add-ins so we can avoid similar issues in the future, as EWS is slated to be deprecated by October 2026. This is the final update for the event.

03:24 PM

Service Restored

User impact: Users may have been intermittently unable to access their Exchange Online mailboxes in some connection methods.
More info: This issue may have intermittently impacted some users who attempted to access the Exchange Online service through the Outlook mobile apps or the new Outlook for Mac desktop client.
Final status: We've monitored the service for an extended period of time and confirmed that error counts have remained below pre-incident levels, confirming remediation.

01:31 PM

Service Degradation

Title: Some users may be unable to access their mailboxes through multiple connection methods in Exchange Online
User impact: Users may be unable to access their mailboxes through multiple connection methods in Exchange Online.

08:43 AM

Title: Some users may be unable to access custom add-ins through any Exchange Online connection method
User impact: Users may have been unable to access custom add-ins through any Exchange Online connection method.
More info: For additional guidance on managing Exchange Web Services, please refer to the following:
https://learn.microsoft.com/en-us/exchange/client-developer/exchange-web-services/how-to-control-access-to-ews-in-exchange
Final status: We’ve identified that a recent Exchange Web Services (EWS) deprecation update and an Exchange Online authentication change prevented users from accessing custom add-ins in Outlook. To remediate this issue, we rolled back both offending changes and verified through service monitoring that this action successfully resolved the impact. Admins that have disabled EWS may continue to experience this issue and we recommend that admins re-enable EWS at this time. For additional guidance on managing Exchange Web Services, please refer to the following:
https://learn.microsoft.com/en-us/exchange/client-developer/exchange-web-services/how-to-control-access-to-ews-in-exchange
Scope of impact: Some users who are attempted to access custom add-ins through all Exchange Online connection methods may have been impacted.
Start time: Thursday, March 12, 2026, at 10:04 PM UTC
End time: Friday, March 27, 2026, at 1:40 AM UTC
Root cause: A recent EWS deprecation update and an Exchange Online authentication change prevented users from accessing custom add-ins in Outlook.

This is the final update for the event.

08:42 AM

Title: Some users may be unable to access the default add-ins in Outlook
User impact: Users may have been unable to access the default add-ins in Outlook.
More info: This issue impacted both the Outlook desktop client and Outlook on the web. Some affected users found that the “My Templates” icon was missing from the Outlook ribbon, and others were unable to find templates in the AppData Microsoft Templates location, even though templates were known to exist and were still being used by non-impacted users. Some users also reported that the Viva Insights add-in was impacted by this event.
Final status: We’ve identified that a recent Exchange Web Services (EWS) deprecation update and an Exchange Online authentication change prevented users from accessing default add-ins in Outlook. To remediate this issue, we rolled back both offending changes and verified through service monitoring that this action successfully resolved the impact. Admins that have disabled EWS may continue to experience this issue and we recommend that admins re-enable EWS at this time. For additional guidance on managing Exchange Web Services, please refer to the following:
https://learn.microsoft.com/en-us/exchange/client-developer/exchange-web-services/how-to-control-access-to-ews-in-exchange
Scope of impact: Some users attempting to access or use the default add-ins within Outlook may have been impacted.
Start time: Thursday, March 12, 2026, at 10:04 PM UTC
End time: Friday, March 27, 2026, at 1:40 AM UTC
Root cause: A recent EWS deprecation update and an Exchange Online authentication change prevented users from accessing default add-ins in Outlook.
Next steps:
- We’re reviewing how the impacting changes prevented users from accessing default add-ins so we can avoid similar issues in the future, as EWS is slated to be deprecated by October 2026.
This is the final update for the event.