401 Error when attempting Test-OutlookWebServices (MS Exchange 2007)

Some users have been recieving 401 Error when attempting to run Test-OutlookWebServices from the CAS server. The below articles talks about why IIS returns this error.
http://support.microsoft.com/?id=896861


You can test this by attemtping to access the server in the following way:
https://netbiosname/Autodiscover/Autodiscover.xml :It will prompt for credentials. After prompting a couple of times we get the following error:Error: Access is Denied.-


Use https://localhost/Autodiscover/Autodiscover.xml :It will work fine and give an output.
DisableLoopbackCheck can be disabled but then the system is left open to an attack and I would not recommend disabling this function unless you will enable once testing is completed.
: Disable the loopback checkFollow these steps:



1.Click Start, click Run, type regedit, and then click OK.


2.In Registry Editor, locate and then click the following registry key:
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.Quit Registry Editor, and then restart your computer.