You try to remove or make a change to a distribution group by using the Exchange admin center in Microsoft Exchange Online for Microsoft Office 365 or in on-premises Microsoft Exchange Server. In this situation, you receive the following error message:
You don't have sufficient permissions. This operation can only be performed by a manager of the group.
This issue occurs if you're not a manager of the group. In this situation, you're not listed in the ManagedBy attribute.
For example, if you're an Exchange Online admin or an Exchange admin who isn't listed in the ManagedBy attribute and you want to make changes to a distribution group that's named Accounting, run the following command to add yourself to the ManagedBy attribute: