Users may be unable to sign in to OneNote using iOS devices

Title: Users may be unable to sign in to OneNote using iOS devices

User impact: 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 we work on remediation, impacted users may be able to utilize 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 status: We've identified that 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. We're deploying a code fix to correct this issue and expect that it'll complete deployment by the time of our next update.

Scope of impact: Any user attempting to sign in to OneNote build 16.112.717.0 or higher using iOS devices is impacted.

Start time: Monday, July 20, 2026, at 4:36 AM UTC

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: Tuesday, August 18, 2026, at 6:00 AM UTC

Title: Users may be unable to sign in to OneNote using iOS devices

User impact: 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 we work on remediation, impacted users may be able to utilize 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 status: We've identified an issue with the OneNote iOS Authenticator broker sign-in and are working on developing and validating a fix to remediate impact.

Scope of impact: Any user attempting to sign in to OneNote build 16.112.717.0 or higher using iOS devices is impacted.

Root cause: An issue with the OneNote iOS Authenticator broker sign-in is preventing users from signing in to OneNote using iOS devices.

Next update by: Friday, August 14, 2026, at 4:00 PM UTC

Title: Users may be unable to sign in to OneNote using iOS devices

User impact: Users may be unable to sign in to OneNote using iOS devices.

Current status: We've identified that a recent change to the sign in flow may be causing impact to occur. We've reverted the change but this did not resolve the issue. We're analyzing OneNote logs from impacted users as well as OneNote logs from our internal reproduction of the issue to assist us in identifying the underlying root cause of impact.

Scope of impact: Any user attempting to sign in to OneNote build 16.112.717.0 or higher using iOS devices is impacted.

Next update by: Friday, August 14, 2026, at 2:00 PM UTC