That's the expected behavior, read here: https://learn.microsoft.com/en-us/exchange/troubleshoot/groups-and-distribution-lists/cannot-manage-dg
Synced distribution group issue
Pavan Panduranga Kasargod
21
Reputation points
Hi All, we have a synced distribution list from AD to on premise. Owner of the group who is migrated to O365 cannot add/remove members in owa/outlook. Tried by updating managed by property and update member checked in on premise AD. Still we are getting error. That the DL should be managed from on premise.