Advisory information Title: Many users will see searches failing in the Outlook desktop client
ID: https://protect-us.mimecast.com/s/qZOBCAD93vtBBzNiGjXlz Status Service Restored Details Title: Many users will see searches failing in the Outlook desktop client User Impact: Users may have experienced search failures in the Outlook desktop client. More info: Users' searches would default to a local search and they would have been unable to search for content that resides within the Exchange Online service. This issue was only affecting on-premises users using non-modern authentication. Users who had access to Outlook on the web may have been able to use that protocol as an alternative method to search the service. Final status: Following a period of monitoring the affected environment, we've confirmed that our fix to correct the routing of search requests has been successful in remediating impact. Scope of impact: This issue may have potentially affected any of your users attempting to search in their Outlook desktop clients. Start time: Monday, May 4, 2020, at 4:00 PM UTC End time: Thursday, May 21, 2020, at 10:00 PM UTC Root cause: A code issue within the authentication process was misrouting search requests, causing some requests to fail. Next steps: - We're reviewing our authentication and search request routing processes, to find ways to prevent this problem from happening again. This is the final update for the event. Thank you,
The Microsoft team | 
Microsoft