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 [...]