Microsoft 365 Alert – Service Degradation – Planner – Some users may be unable to access Planner on the web – RESOLVED

Announcements Arpan Das

02/03/2026 15:55:00 PM

NHSmail Reference: INC46762438

Microsoft Reference: PL1242549

Issue Status: RESOLVED

Issue Description: Users may be unable to access Planner on the web.

More Info: As a workaround, some users may be able to access Planner via Microsoft Teams.

Final Update: 03/03/2026 8:15:00 AM – Microsoft has confirmed with a subset of affected users that updating the Microsoft Authentication Library (MSAL) to resolve the mismatch has remediated the impact.

Scope of impact: Some users that are trying to access Planner on the web may be impacted.

Root cause: An update to the Planner MSAL introduced a mismatch between the unauthenticated Planner on the web landing page and the authenticated experience after users signed in. This mismatch resulted in the impact.

Next steps: Microsoft are reviewing our standard update protocol to ensure future updates are applied with the proper cadence to prevent similar mismatches from occurring.