Some users may be unable to load pages with custom apps or webparts in SharePoint Online and get an error

Title: Some users may be unable to load pages with custom apps or webparts in SharePoint Online and get an error

User impact: Users may be unable to load pages with custom apps or webparts in SharePoint Online and get an error.

More info: The following error may be encountered by users when attempting to load an affected page:
An error occurred during the compilation of the requested file, or one of its dependencies. 'Microsoft.SharePoint.IdentityModel.SPAuthFlightController' does not contain a definition for 'IsRemoveRedirectWithProofTokenOnSignInPageEnabled'

Current status: We've completed development of and are deploying a code fix to correct the authentication issue. We'll provide a timeline for impact remediation as one becomes available.

Scope of impact: Some users may be unable to load pages with custom apps or webparts in SharePoint Online and get an error. This section may be updated as our investigation continues.

Root cause: A recent change intended to update the authentication flow has mistakenly removed a necessary authentication component, resulting in impact.

Next update by: Wednesday, November 19, 2025, at 9:00 PM UTC

Title: Some users may be unable to load pages with custom apps or webparts in SharePoint Online and get an error

User impact: Users may be unable to load pages with custom apps or webparts in SharePoint Online and get an error.

More info: The following error may be encountered by users when attempting to load an affected page:

An error occurred during the compilation of the requested file, or one of its dependencies. 'Microsoft.SharePoint.IdentityModel.SPAuthFlightController' does not contain a definition for 'IsRemoveRedirectWithProofTokenOnSignInPageEnabled'

Current status: We've determined that a recent change intended to update the authentication flow has mistakenly removed a necessary authentication component, resulting in impact. We're developing a fix to address this issue.

Scope of impact: Some users may be unable to load pages with custom apps or webparts in SharePoint Online and get an error. This section may be updated as our investigation continues.

Root cause: A recent change intended to update the authentication flow has mistakenly removed a necessary authentication component, resulting in impact.

Next update by: Tuesday, November 18, 2025, at 7:30 PM UTC

Title: Some users may be unable to load pages with custom apps or webparts in SharePoint Online and get an error

User impact: Users may be unable to load pages with custom apps or webparts in SharePoint Online and get an error.

More info: The following error may be encountered by users when attempting to load an affected page:

An error occurred during the compilation of the requested file, or one of its dependencies. 'Microsoft.SharePoint.IdentityModel.SPAuthFlightController' does not contain a definition for 'IsRemoveRedirectWithProofTokenOnSignInPageEnabled'

Current status: We're investigating a potential issue with SharePoint Online and checking for impact to your organization. We'll provide an update within 30 minutes.