When you use a fully qualified domain name (FQDN) or a custom host header to visit a Microsoft SharePoint Server 2010 Web site or a Microsoft SharePoint Foundation 2010 Web site from the server that is hosting the Web site, you receive a blank page.
Note You only receive a blank page if you try to visit the Web site directly from the server. If you visit the Web site from a client computer, you can view the Web site.
This problem occurs when the Web site uses Windows Integrated Authentication and the Web site has a name that is mapped to the local loopback address.
To work around this problem, disable the loopback check or specify host names.
For more information about how to disable the loopback check or specify host names, click the following article number to view the article in the Microsoft Knowledge Base:
896861 You receive error 401.1 when you browse a Web site that uses Integrated Authentication and is hosted on IIS 5.1 or a later version