- A user who has a mailbox in legacy dedicated is listed in the address book together with an icon that represents an external contact.
- When you try to add another mailbox in Microsoft Outlook, you receive the following error message:
- When you try to add a delegate or folder/calendar permissions in Outlook, the user is listed with a red slash over the icon, and then you receive an error message similar to the following:
For an object to be synchronized to vNext as an ACLable object, the msExchRecipientDisplayType value for the user object in the on-premises AD must have a value of 0. This indicates that the object is equal to a MailboxUser and should be an ACLable object in Exchange vNext. This allows vNext mailbox users to add delegates and to add more mailboxes in Outlook for users who have mailboxes in the legacy dedicated environment.
Note Room mailboxes and room lists should not be set to a value of 0 like users and shared mailboxes. For the resources to function successfully during coexistence, they have special values, as documented in KB 3172266 - You can't view room lists after migration to Office 365 Dedicated vNext from legacy dedicated.
You should contact your organization's Identity/Active Directory team to request that the msExchRecipientDisplayType attribute be updated. And after the change is made, you will need to allow time for the change to synchronize to Azure AD and Exchange vNext.
Article ID: 3187967 - Last Review: Jun 5, 2017 - Revision: 13