Ran into this recently where I could browse the SharePoint 2010 site from any machine or server in the environment from the internal and external networks but could not browse to it from the SharePoint server itself.  This issue typically occurs in one server deployments and is easy to resolve.

Enter the old DisableLoopBackCheck registry change.   Just regedit to
<div><strong>HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlLsa</strong></div>
<div><strong> </strong></div>
<div>and add a DWORD value set to 1 for a entry called DisableLoopbackCheck.  Reboot and all should be good.</div>