Microsoft 365 Alert – Service Degradation – Microsoft Teams – Some users with Technical Preview access may be unable to modify existing webinars in Microsoft Teams – ONGOING

Announcements Arpan Das

12/05/2026 09:07:00 AM

NHSmail Reference: INC46823710

Microsoft Reference: TM1308375

Issue Status: ONGOING

Issue Description: Users with Technical Preview access may be unable to modify existing webinars in Microsoft Teams.

Current Update: 12/05/2026 14:55:00 PM– Microsoft are actively reverting the aforementioned Teams service update to mitigate impact. They anticipate that the deployment will complete by Thursday, May 14, 2026, which should resolve the issue.

Scope of impact: Impact is specific to some users who have early release or technical preview access attempting to update existing webinars in Microsoft Virtual Events powered by Teams. This information may be updated as our investigation continues.

Root cause: A recent Microsoft Teams service update extending sensitivity-based access control to webinars inadvertently introduced a regression where updates to existing webinars are incorrectly treated as changes to event access type, resulting in impact.

Next update by: Wednesday, May 13, 2026, at 1:00 PM UTC