How to Disable loopback check

Some times we might get 401.1 Access denied error when trying to access the fully qualified domain name (FQDN) of our SharePoint site from the server. To fix this add a registry key to disable the loopback check. There are two options to do this.

By Manually

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following registry subkey: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
3. Right-click Lsa, point to New, and then click DWORD Value.
4. Type DisableLoopbackCheck, and then press ENTER.
5. Right-click DisableLoopbackCheck, and then click Modify.
6. In the Value data box, type 1, and then click OK.
7. Exit Registry Editor.

By Power Shell Command

New-ItemProperty HKLM:\System\CurrentControlSet\Control\Lsa -Name "DisableLoopbackCheck" -value "1" -PropertyType dword

Make sure to reboot your server afterwards.
Hope this helps...