Delegated permissions are successfully modified in Exchange but not Active Directory – PRB0171899 Local admins may see an issue when trying to remove delegation permissions on User Accounts, Shared Mailboxes or even Distribution Lists.
Issues with delegate users and shared mailbox permissions – PRB0171899 We are aware of issues around users not being able to send emails from shared mailboxes and accounts that they have delegate access to if the mailbox is not appearing in their “permissions” tab in portal.
