Microsoft 365 Alert – Service Degradation – Exchange Online – Users may intermittently be unable to “Reply All” to email messages using a group mailbox in Outlook on the web – ONGOING

15/09/2023 11:47:00 AM (GMT)

NHSmail Reference : INC38279595

Microsoft Reference : EX673361

Issue Status : ONGOING

Issue Description : Users may intermittently be unable to “Reply All” to email messages using a group mailbox in Outlook on the web.

More info : Affected users intermittently receive the following error message when attempting to “Reply All” from a group mailbox in Outlook on the web: “This message can’t be sent right now. Please try again later. Set action is invalid for property.” The impact can be bypassed by replying to these messages from outside of a group mailbox.

Current Update : 27/09/2023 08:35:00 AM – After Microsoft’s investigation into the PostGroupItem API behavior, they suspect that the API is not a factor contributing to the underlying cause of the issue. They are attempting to reproduce the issue internally with a test account to help them locate what other factors may be contributing to the underlying cause of the issue and to develop a potential action plan for resolving impact.

Scope of impact : This event may intermittently impact users who attempt to “Reply All” to email messages using a group mailbox in Outlook on the web.

Root cause : A code change meant to improve conversation grouping is causing the intermittent “Reply All” impact.

Next update by : Saturday, September 30, 2023, at 7:00 AM UTC