When attempting to add delegate by using Outlook, the error "The Delegate settings were not saved correctly. Unable to activate send-on-behalf-of list. You do not have sufficient permission to perform this operation on this object" is encountered.
The issue may occur if:
1. Configuring a delegate for someone else when you are not logged into Windows under that account.
For example, log into Windows as UserA and start Outlook with a profile for UserB"s mailbox. Then, try to add UserC as the delegate for UserB. In this scenario you will get the above error.
2. Error adding delegate when you do not have access to a “writable” global catalog server
If your Outlook client does not have access to a GC where you can write AD properties you will receive the above error when you attempt to add a delegate. I would like to explain that the issue is by design. Neverthless, there is a post SP3 Outlook 2003 hotfix and an Outlook 2007 hotfix developed to make Outlook work better in this scenario.
Before this hotfix was created, the "Send on Behalf" (PublicDelegates) permission was considered a mandatory part of adding a delegate. This hotfix lets you add the delegate without setting the "Send on Behalf" (PublicDelegates) property.
For additional details on this fix, please see the following articles:
946208 Error message when you try to add a delegate in Outlook 2003: "The Delegates settings were not saved correctly"
950794 Error message when you try to add a delegate in Outlook 2007: "The Delegates settings were not saved correctly"
3. The SELF account does not have the "Write Personal Information" right on the user account that is trying to add the delegate.
Note: Support for delegation across multiple Outlook versions is NOT supported if either the manager or delegate is using Outlook 2007. This is a change from earlier Outlook versions where cross-version support was “not recommended.”
Please see the following article for further details.
924470 - The delegates and the manager must all use Outlook 2007 when you use delegates in Outlook 2007