Unable to configure Outlook 2007/2010 on Exchange Server 2007/2010

The below error message is showed at what time you attempt to build up Out of Office Assistant in Microsoft® Office® Outlook® 2007 or Microsoft Office Outlook 2010 on a Microsoft Exchange Server 2007 or Microsoft Exchange Server 2010. Nothing is right here what I should do to resolve it please help?

Microsoft Office Outlook
Your Out of Office settings cannot be displayed, because the server is currently unavailable.
Try again later.
OK
