Microsoft 365 Alert : Service Degradation – Exchange Online – Some users receive a security certificate revoked message prompt in the Outlook desktop and mobile app platforms – RESOLVED
03/11/2022 07:25:00 AM (BST)
NHSmail Reference : INC32541080
Microsoft Reference : EX455084
Issue Status : RESOLVED
Issue Description : Some users receive a security certificate revoked message prompt in the Outlook desktop and mobile app platforms.
More info : While Microsoft is focused on remediation, users can click on the Ok button in the prompt or restart the affected app to bypass the message without encountering any impact to app functionality.
Scope of Impact : Your organization is being affected by this event, and some users receive a security certificate revoked message prompt in the Outlook desktop and mobile app platforms.
Final Update : 14/11/2022 15:40:00 PM – Microsoft’s analysis of the Outlook client diagnostic and memory process logs identified a subset of network infrastructure that processes Transport Layer Security (TLS) requests wasn’t functioning as expect, resulting in impact. They have disabled this problematic network path, allowing traffic to flow through alternate routes and remediating impact.
Next steps : Microsoft is identifying methods of bolstering the reliability of TLS infrastructure to prevent similar impact from occurring in the future. They are analyzing their findings from this event’s investigation to improve their network infrastructure monitoring to more quickly detect and address issues of this nature.