All of our Outlook 2011 users are unable to connect to Exchange 2010 outside the office.  When the users are inside the office Outlook 2011 connects fine.  Does Outlook 2011 need a special certificate assisnged?  Does basic authentication need to be enabled on Exchange Server?  Any help would be appreciated!

Any testing i can do with the server?  https://mail."example".com/ews/exchange.asmx