BlackBerry Internet Service cannot connect to a Microsoft Outlook Web Access account using Microsoft Exchange 2007 or Microsoft Exchange 2010

When we publishing Exchange 2007 or Exchange 2010, we used to get a complain from Black Berry users that they cannot connect to there mail from Black Berry Devices.. This is because The Microsoft Exchange Web Services (EWS) component is required to be active on the Microsoft Exchange Server.

Check the below URL from Black Berry regarding this issue.

http://www.blackberry.com/btsc/search.do?cmd=displayKC&docType=kc&externalId=KB18567

so, you need to publish EWS service on your firewall or TMG as describe in the above URL.