Microsoft 365 Alert – Service Degradation – Microsoft 365 apps – Users may be unable to sign in to OneNote using iOS devices – ONGOING

Announcements Shagufta Naaz

17/07/2026 08:48:00 AM

NHS.net Connect Reference: INC46910385

Microsoft Reference: OP1454727

Issue Status: ONGOING

Issue Description: Users may be unable to sign in to OneNote using iOS devices.

More info: Impact is specific to users with OneNote build 16.112.717.0 or higher.

Whilst Microsoft work on remediation, impacted users may be able to utilise OneNote on the web or remove Authenticator so that authentication falls back to the in-app webview. Users may also be able to sign in to any other Microsoft 365 apps first (e.g. PowerPoint), then attempt to sign in again in OneNote.

Current Update: 04/09/2026 09:16:00 AM – Microsoft has completed the validation of their fix in their internal testing environment and are preparing it for deployment, which should complete by their next scheduled update. Additionally, they have received confirmation from a subset of users who reported the issue that the fix resolves impact.

Scope of impact: Any user attempting to sign in to OneNote build 16.112.717.0 or higher using iOS devices is impacted. This information may be updated as the investigation continues.

Root cause: A code change included in OneNote builds 16.112.717.0 and above, designed to change how authentication requests are routed, introduced an issue with OneNote iOS Authenticator broker sign-in and is causing impact.

Next update by: Thursday, September 17, 2026, at 10:00 AM UTC