Microsoft 365 Alert – Service Degradation – Microsoft Teams – Some users are unable to join Microsoft Teams meetings with more than 1,000 attendees and view-only enabled – RESOLVED

30/11/2023 08:40:00 AM

NHSMail Reference: INC39937723

Microsoft Reference: TM694366

Issue Status: RESOLVED

Issue Description: Users were unable to join Microsoft Teams meetings with more than 1,000 attendees and view-only enabled.

More info: After the main meeting’s capacity of 1,000 attendees was reached, additional attendees were unable to join with a view-only experience as expected. The impact occurred using any connection method, such as the Microsoft Teams desktop client, mobile app, and web browsers

Final Update: 30/11/2023 08:40:00 AM – Microsoft identified a recent change that caused the meeting attendee totals to be incorrectly calculated. They have disabled the change and confirmed the impact is resolved.

Scope of impact: Your organization was affected by this event, and it impacted some users who attempted to join Microsoft Teams meetings that contained more than 1,000 attendees.

Root cause: A recent change caused meeting attendee totals to be incorrectly calculated, which caused the Microsoft Teams service to believe the maximum number of attendees was reached.

Next steps: To help prevent similar impact in the future, Microsoft are investigating why the change affected meeting attendee totals and how they can improve their validation procedures to catch such issues before changes are made.