What is Autodiscover and why it is required.

In order for Exchange 2007-2013 and Outlook 2007-2016 to function properly, you should have a the Autodiscover CNAME record set up for your domain name which points to our Exchange server.

You need to set up the Autodiscover record for your domain name to have the following features:

• Automatic setup for Outlook 2007 through 2016.
• Automatic setup for Outlook for Mac, Entourage with EWS and Mac Mail.
• Free/Busy information in your calendar.
• Access Out of Office response in Outlook.
  Note: users can still set out of office through OWA regardless if Autodiscover is setup or not. 
• Download offline address book.
• Share folders by sending out Sharing invitation.
• Access to Public Folders in Exchange 2013.