28/04/2022 08:52:00 AM (BST)
Issue Reported : 26/04/2022 09:53:00 PM
Microsoft Reference : EX365060
NHSmail Reference : INC28649784
Issue Status : RESTORED
Issue Description : Users aren’t receiving free/busy information for users in external organizations.
Scope of impact : This issue may have potentially affected any of your users attempting to view free/busy information for users in external organizations.
Final Update : 29/04/2022 02:35:00 PM – Microsoft completed the configuration change and deployed it to the affected infrastructure. Their telemetry along with several user confirmations show that the issue is now remediated.
Root cause : An authentication component responsible for what status information from external users were provided to internal users fell out of sync.
Next steps : Microsoft are investigating the cause of the authentication component issue to better understand how to prevent this issue from happening again.