I have just installed a new CRM 4.0 with a SQL Server 2008 64bit & Windows Server 2008 64bit, when I open IE7 with http://servername:port/orgname , after type the user name and password in windows authentication dialog box(domain administrator), the CRM Web site was give me below information:
"No Microsoft Dynamics CRM user exists with the specified domain name and user ID A Microsoft Dynamics CRM user record does not exist with the specified domain nameand user ID."
but when I use the http://IP Address /orgname, it's work.