Microsoft 365 Alert – Service Degradation – SharePoint Online – Some users may be unable to access SharePoint Online sites configured with Authentication Context – RESOLVED

Announcements Sharmista Mohanta

01/09/2026 09:00:00 AM

NHS.net Connect Reference: INC46923176

Microsoft Reference: SP1464785

Issue Status: RESOLVED

Issue Description: Users may be unable to access SharePoint Online sites configured with Authentication Context.

More info: Specifically, users were unable to access SharePoint Online sites configured with Authentication Context through sensitivity labels.

Users received the following error message:
“Server Error in ‘/’ Application.”

As a workaround, users may have been able to temporarily access the affected content by first clearing internet browser cookies and navigating to the root site collection before opening the direct link. Users could have also opened a new browser tab on the same session and access the site or used a direct link.

Final Update: 07/09/2026 10:03:00 AM – After confirming that Microsoft’s reversion of the code update to the SharePoint Online authentication process completed as expected and was available in all environments, they validated with a portion of impacted users that access to SharePoint Online sites configured with Authentication Context has been restored.

Scope of impact: Some users attempting to access SharePoint Online sites configured with Authentication Context through sensitivity labels may have been impacted.

Root cause: A recent SharePoint Online code change intended to update authentication processing resulted in Authentication Context requests not being processed as expected, preventing some users from accessing affected sites.

Next steps: Microsoft is continuing to optimise their quality assurance processes to minimise user impact while ensuring important service health updates are deployed as efficiently as possible.