- You deploy Exchange Server 2016 in a cross-forest topology.
- You configure availability service in untrusted forest to share free/busy information.
- You use the Scheduling Assistant feature to view the free/busy information about another forest mailbox in Outlook.
In this scenario, you could only see "\\\\\\\" in the free/busy information. In addition, the Outlook on the web (previously known as Outlook Web App) client is also affected.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.