Cannot Authenticate When Trying to Access Site While Logged onto the Web Server

ASP.NET.  Visual Web Developer 2012.  Windows Server 2008 R2.  IIS 7.  Authentication Mode "Windows."
I am trying to test my web site by loggin in to the site while logged onto the web server that hosts the site.  I enter valid Windows credentials.  But the login prompt keeps coming back up.  I can log into the site from other computers, just not from the web server.  How can I remedy this?  Thanks for the help.
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