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

Announcements Arpan Das

12/05/2026 09:07:00 AM

NHSmail Reference: INC46823710

Microsoft Reference: TM1308375

Issue Status: RESOLVED

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

Final Update: 20/05/2026 9:2500 AM – Microsoft has completed reverting the aforementioned update and confirmed impact is no longer occurring after a period of monitoring.

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 their 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 steps : Microsoft are reviewing our service update procedures to help prevent similar impact from happening again.