Intermittent Access Issues with Office 365 Apps via Okta

We sincerely apologize for any impact this incident has caused to you, your business, or your customers. At Okta, trust and transparency are our top priorities. Outlined below is the RCA summary for a recent incident where a third-party provider or downstream service experienced an issue that impacted the Okta service. We are committed to implementing improvements to the service to prevent similar occurrences. Detection and Impact: On September 15, 2026, at 06:33 UTC, Okta customers utilizing identity provider-initiated sign-on flows for Office 365 Outlook, Calendar, and People applications began encountering intermittent HTTP 401 Unauthorized errors upon redirection. End users successfully completed authentication through Okta, but were unable to reach the target applications when selecting application tiles. Root Cause Summary: An architectural update to Microsoft’s infrastructure inadvertently affected incoming requests via legacy application redirection paths, resulting in HTTP 401

The intermittent issue affecting Microsoft 365 applications has been addressed. Our monitoring shows a return to normal conditions. Our team is collaborating with our third-party vendor to identify the underlying root cause, and a Root Cause Analysis will be forthcoming.

Okta teams are observing steady recovery across all environments following the deployment of a fix by our third-party vendor. As our Engineering teams continue post-remediation monitoring to ensure lasting platform stability, users who previously experienced redirection failures are now encouraged to re-test application access via their standard dashboard chiclets. Additional updates will be shared as recovery fully stabilizes across all tenant environments.

We continue to track the issue intermittently affecting Microsoft 365 applications. Our third-party vendor has completed the fix and is actively rolling out. We anticipate an additional 24 hours to complete remediation and verify service stability. We will provide our next update by September 18, 2026, 4 PM PDT, or sooner if new details become available. Thank you for your continued patience as we work with the vendor to resolve this issue.

Our third-party vendor has identified the root cause that is intermittently impacting Microsoft 365 services and is currently deploying a fix. The deployment is underway as of September 15, 2026, though complete propagation across all user accounts is expected to take approximately 48 hours to fully resolve the issue. We are actively monitoring the rollout progress and will provide further updates as new details become available. Additional root cause information will be available once the vendor has fully completed the rollout of the fix and validated full resolution.

Active troubleshooting with our vendor remains a high-priority escalation across both engineering teams. While root cause determination is still underway, we understand the operational impact and are fully focused on driving this to resolution. Our next update will be posted as soon as new details are available.

We are continuing to work directly with our third-party service provider to troubleshoot and resolve the intermittent HTTP 401 redirect errors affecting Office 365 applications. We will provide another update as soon as new details are available.

Okta Engineering teams are actively working on a solution and coordinating with the service vendor to restore direct tile functionality. We'll provide an update in 30 minutes, or sooner, as additional information becomes available.