Microsoft 365 Alert – Service Degradation – Exchange Online – Users may be unable to view free/busy status for Gmail users within the Exchange Online calendar – ONGOING

22/05/2026 08:31:00 AM

NHSmail Reference: INC46832712

Microsoft Reference: EX1310533

Issue Status: ONGOING

Issue Description: Users may be unable to view free/busy status for Gmail users within the Exchange Online calendar.

More info: Affected users may see an “Unknown” status for the external Gmail contacts.

Current Update: 04/06/2026 08:44:00 AM – Microsoft has completed the validation of our fix; however, they has identified that a separate issue is preventing deployments from initiating within the affected infrastructure. They are working to resolve this separate issue in order to deploy their fix and remediate impact, and they will aim to provide a timeline for this process as one becomes available.

Scope of impact: Impact is specific to any user attempting to view free/busy status for Gmail contacts in their Exchange Online calendars.

Root cause: Basic Authentication credentials aren’t being correctly forwarded to the third-party service, resulting in the failures to obtain free/busy status responses and causing impact.

Next update by: Thursday, June 04, 2026, at 8:30 PM UTC