NFF

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

On October 28, 2026, at 9:45 AM PT, the Engineering Team became aware of an issue with the email service that caused delayed or failed delivery of outbound SMS messages, including two-factor authentication (2FA) verification codes and SMS alerts. Initial findings indicate this is tied to a service disruption with our downstream telephony carrier, China Mobile. Users waiting on verification codes may experience delays of several minutes. If available, please opt for backup verification methods such as authenticator apps or email. We are actively working with the carrier to monitor the situation and will share our next update as soon as more information becomes available.

Following further investigation, we have confirmed that the USA9014 instance is not impacted by the formatting issue affecting Lightning Web Runtime sites. We continue to investigate and address the issue across affected instances. We'll provide an update in 60 minutes or sooner if additional information becomes available, and apologize for any inconvenience this issue may be causing.