Microsoft 365 Alert – Service Degradation – Exchange Online – Users may see that after selecting a meeting room when scheduling meetings, it changes from available to unavailable – RESOLVED

19/03/2026 09:25:00 AM

NHS.net Connect Reference: INC46777325

Microsoft Reference: EX1233142

Issue Status: RESOLVED

Issue Description: Users may see that after selecting a meeting room when scheduling meetings, it changes from available to unavailable.

More info: While we are working to remediate the impact, admins can mitigate the issue by assigning the desired working hours and the time zone for the meeting rooms.

Final Update: 07/07/2026 09:36:00 AM – Microsoft has deployed their fix to address the offending code complication and confirmed that this process has completed. They have validated with a subset of affected users and from their service telemetry that their actions successfully remediated impact.

Scope of impact: Any users that are trying to select a meeting room when scheduling meetings outside the room’s working hours in Exchange Online may be impacted. This information may be updated as our investigation continues.

Root cause: A recent expansion of the feature logic used to book rooms for scheduled meetings contains a code complication which automatically sets the meeting rooms’ default working hours to appear in Pacific Standard Time instead of their accurate time zone.

Next Steps: Microsoft are analyzing the offending feature logic change to isolate why the potential for impact wasn’t caught prior to deployment. This further analysis will help us to understand how they can update our processes moving forward to ensure similar impact scenarios don’t occur in the future.