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

Title: Users may intermittently be unable to “Reply All” to email messages using a group mailbox in Outlook on the web
User impact: 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 status: We’re continuing our efforts to reproduce the issue internally with a test account to gain more insight into the source of the 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.
Start time: Friday, August 4, 2023, at 5:32 PM UTC
Root cause: A code change meant to improve conversation grouping is causing the intermittent “Reply All” impact.
Next update by: Tuesday, October 3, 2023, at 7:00 AM UTC