WHD user authentication API not working as per documentation instructions.

We are receiving following error when testing API based authentication. Could you please review and let us know if there any issue with our testing or if we need to do something on the server to enable API connections to WHD. We are testing with a valid user (the same user can log in via UI)

PS C:\Windows\System32\WindowsPowerShell\v1.0> curl "">localhost/.../1
curl : The remote server returned an error: (401) Unauthorized.
At line:1 char:1
+ curl "localhost/.../1 ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-WebRequest], WebExc
eption
+ FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeWebRequestComman

PS C:\Windows\System32\WindowsPowerShell\v1.0> curl "">localhost/.../1
curl : The remote server returned an error: (401) Unauthorized.
At line:1 char:1
+ curl "localhost/.../1 ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-WebRequest], WebEx
ception
+ FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeWebRequestCommand