Loopback Issues?
Site Collection Admin Not Authenticating
I was in the process of building out a new SharePoint 2013 environment to host Team Foundation Server 2013 Preview and Project Server 2013. Ran into a situation where my user account, a site collection administrator, could not login to the site when I was logged into the server. Essentially the browser would just continue to prompt me for credentials. However, if I tried to connect using my local machine, everything worked great.
My application architect then pointed me at the following article that talked about the loopback issue that can occur on Windows Server environments. Apparently this is quite common, but since it was the first time I was blessed with experiencing this marvelous feature I thought I would share.
http://daniecsp.blogspot.com/2012/11/sp2010-sp2013-disableloopbackcheck.html