Security Issues with IIS, Authentication Providers, HTTP 401 status codes

We could not authenticate to IIS, except from the local machine. Even basic authentication would send back 401.1 and 401.2 HTTP status codes (I checked this by examining the IIS logs). 401.1 is invalid username/password, but 401.2 is login failed due to server configuration. A coworker helped me with the following:

1. Start a command prompt, then navigate to the C:\Inetpub\Adminscripts folderwhere the adsutil.vbs located.
2. Check the authentication providers with this in the command prompt: cscript adsutil.vbs get w3svc/NTAuthenticationProviders
3. If you get "The parameter "NTAuthenticationProviders" is not set at this node" message, then type cscript adsutil.vbs set w3svc/NTAuthenticationProviders "NTLM"