Consider the following scenario:
- You use the Windows or Outlook for Mac client to connect to Exchange Server 2016.
- You are assigned as a delegate on another user's account.
- The Delegate can see my private items option is enabled on the user's account.
- Some calendar items are marked as "Private" on the user's account.
In this scenario, you can't retrieve correct free/busy information about the user's account. In this case, the time slot information about "Private" items is presented as Free.
This issue occurs because Exchange Web Services (EWS) calls do not return the items that are marked as Private.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.