Consider the following scenario:
- You grant Full Access permission to a user on a non-user mailbox (such as resource mailbox) in a Microsoft Exchange Server 2010 environment.
- You grant the user Send As permission and Write Personal Information permission for the non-user mailbox.
- The user tries to add delegates or tries to remove delegates from the non-user mailbox by using Office Outlook.
The Delegates settings were not saved correctly. Cannot activate send-on-behalf-of list. You do not have sufficient permission to perform this operation on this object.