When end users mailboxes are migrated to Exchange Online from Exchange on premises the users' ability to manage email enabled on premises directory distribution groups in Microsoft Outlook is impacted. The users' Outlook is no longer connecting to the on premises directory service. While Outlook will have visibility to the synchronized representation of the on premises email enabled distribution groups those synchronized groups are not directly editable in the online directory.
As an alternative to using Outlook to manage Distribution Groups users have access to the Exchange Control Panel (ECP), a web interface that is a native part of Microsoft Exchange for end user and administrative access to Exchange features. However, access to the ECP for end users is typically tied to having a Mailbox in the same Exchange environment. Because of this dependency for typical ECP access by end users, when a user mailbox is migrated to Exchange Online, the user's