Exchange Online
Users can still send the message successfully and it is delivered even though Outlook and OWA reports this error. My users have recently started getting this error message when sending mail to a distribution group with delivery restrictions. The group is configured so only users in the distribution group can send mail to the distribution group.
I have also tested another distribution group with only myself in it, but the same permissions as the previous group and continue to receive the same error.
Users have permission to send to the group and mail sent to the group is delivered successfully so why do they get this error message when it is obviously not accurate?
I have narrowed the timing of this issue down. We began having this problem after out tenant upgrade to version 15.1.355.11 earlier this week. We were not having this problem on our previous tenant version.
The problem occurs when the group has delivery restrictions in place AND allowed sender is a group with another group inside of it.
I can easily recreate this issue with 2 groups and 1 user. This affects both onprem and cloud groups.
