Microsoft 365 Alert : Service Degradation – Exchange Online – Some users may be unable to access their Exchange Online mailboxes via any connection method – RESOLVED

21/06/2022 01:59:00 PM (BST)

Microsoft Reference : EX394347  

NHSmail Reference : INC29840709

Issue Status : RESOLVED

Issue Description : Users were unable to access their Exchange Online mailboxes via any connection method.

More info: Outlook on the web was also impacted. Affected users would have encountered delays and failures when creating, sending, receiving, or accessing email messages.
Additionally, affected users also experienced reduced search functionality within the impacted services, including Outlook Room Finder.

Scope of impact : Impact was most severe in Western Europe but would also have impacted a small percentage of users located throughout EMEA, North America, and the Asia-Pacific regions.

Final Update : 22/06/2022 08:59:00 AM – Microsoft confirmed from their updated service monitoring that all services remain healthy following the targeted restarts. Additionally, they completed investigations into the potential remaining impact to Outlook on the web and confirmed that this is a known issue which is unrelated to this event.

Root cause : An infrastructure power outage necessitated failing over Microsoft 365 traffic management servicing users primarily in Western Europe. This action failed to properly complete, leading to functional delays and access failures for several Microsoft 365 services.