Microsoft 365 Alert – Service Degradation – Exchange Online – Delegate users may be unable to send emails to contact lists for shared mailboxes in Outlook on the web – RESOLVED

Announcements Habiba Tabasum

21/09/2023 13:23:00 PM (GMT)

NHSmail Reference : INC38412199

Microsoft Reference : EX673417

Issue Status : RESOLVED

Issue Description : Delegate users may be unable to send emails to contact lists for shared mailboxes in Outlook on the web.

More info : While Microsoft are focused on remediation, users may be able to use Outlook desktop and mobile app to bypass the impact. Furthermore, affected users may be able to browse to the contact list in the ”PeopleHub” and click the ”Send Email” button on the desired contact list.

Final Update : 13/10/2023 08:42:00 AM – Microsoft successfully deployed the fix to repair the regression and confirmed that impact has been remediated.

Scope of impact : Impact is specific to any delegate user, served through the affected infrastructure, attempting to send emails to contact lists for shared mailboxes in Outlook on the web.

Root cause : A recent service update, intended to update the APIs used for contact searching in Outlook on the web, inadvertently contains a code regression that’s resulting in impact.