I am having trouble connecting Microsoft Outlook 2007 to Microsoft Exchange Server 2003. This problem is very sudden. Three computers that were previously connecting to the server without any trouble are suddenly not connecting or loading outlook at all. When I do try to load Outlook, it takes a really long time and then gives the error "Microsoft Exchange is unavailable". Options are 'retry', 'work offline' and 'cancel'. If i click retry, then it sometimes connects. Most of the time though, it will just produce the error again. Click work offline and then it will say "Folders unavailable" and usually quit. Click cancel and it just quits. Additionally, when I attempt to enter the server and mailbox account information, it puts it into the dialogs, but will not underline it indicating that it has found it. Any suggestions? Right now, we would be happy if we were just able to download the mailboxes, contacts, and calendars onto the local machines.Here is the closest thing to it that I can find to it on Microsoft Support (it doesnt help though) http://support.microsoft.com/kb/927481

You should first check all your DNS settings on the servers and clients And verify dns lookup querries Deli