Some users were unable to see conference room availability for Exchange Online through a room-booking application

Title: Some users were unable to see conference room availability for Exchange Online through a room-booking application User impact: Users were unable to see conference room availability for Exchange Online through a room-booking application. More info: Affected users may have received HTTP 403 Forbidden errors when attempting to retrieve room mailbox availability data, which prevented meeting room availability lookups, booking, and scheduling operations. Final status: We've completed the reversion of the aforementioned change and confirmed after an extended period of monitoring that impact has now been remediated. Scope of impact: Impact was specific to some users attempting to see conference room availability for Exchange Online through the affected third-party room-booking application. Start time: Monday, July 13, 2026, at 9:00 PM UTC End time: Tuesday, July 14, 2026, at 8:29 AM UTC Root cause: A recently enabled service change affected how free/busy request tokens were processed, resulting in HTTP 403 errors when users attempted to retrieve conference room mailbox availability information. Next steps: - We're reviewing our service change validation procedures to better identify similar issues during our development and testing cycles. This is the final update for the event.

Title: Users are unable to see conference room availability for Exchange Online through a room-booking application User impact: Users are unable to see conference room availability for Exchange Online through a room-booking application. More info: Affected users may receive HTTP 403 Forbidden errors when attempting to retrieve room mailbox availability data, which can prevent meeting room availability lookups, booking and scheduling operations. Current status: We've identified that a recently enabled service change is affecting how free/busy request tokens are processed, resulting in HTTP 403 errors when users attempt to retrieve conference room mailbox information. We're reverting the offending change to remediate the issue and are monitoring the deployment of the rollback to confirm it successfully restores service. We expect to provide a completion timeline when one becomes available. Scope of impact: Your organization is affected by this event, and any user attempting to see conference room availability for Exchange Online through the affected third-party room-booking application are impacted. This information may be updated as our investigation continues. Start time: Monday, July 13, 2026, at 9:00 PM UTC Root cause: A recently enabled service change is affecting how free/busy request tokens are processed, resulting in HTTP 403 errors when users attempt to retrieve conference room mailbox information. Next update by: Tuesday, July 14, 2026, at 11:00 AM UTC

Title: Users are unable to see conference room availability for Exchange Online through a room-booking application User impact: Users are unable to see conference room availability for Exchange Online through a room-booking application. Current status: We're analyzing the error logs to help identify the source of the issue, which will help us determine our next troubleshooting steps. Scope of impact: Your organization is affected by this event, and the issue impacts any user attempting to see conference room availability for Exchange Online through the affected third-party room-booking application. This information may be updated as our investigation continues. Next update by: Tuesday, July 14, 2026, at 9:00 AM UTC

Title: Users are unable to see conference room availability for Exchange Online through a room-booking application User impact: Users are unable to see conference room availability for Exchange Online through a room-booking application. Current status: We're investigating a potential issue with Exchange Online and checking for impact to your organization. We'll provide an update within 30 minutes.