Exchange Server 2013 is not supported on Outlook 2007 out of the box. In order to connect with your mailbox using Outlook 2007, you must apply the most recent Outlook 2007 updates before attempting to configure the mailbox.

For more information on the Outlook versions that are supported by Exchange 2013, go to this page on Microsoft’s TechNet wiki. Click here to download the latest update package for Outlook 2007.