Orchestrator API, WindowsAuthentication (NTLM), adding asset format error 403

Hi,

I’m trying out capabilities of Orchestrator API with C# code (Visual Studio).
My authentication is done with Windows Authentication. I’m able to connect to Orchestrator and retrieve data with GET methods.

I’m having trouble with POST, creating of items.
I’m trying to achieve asset creation

Used json load

Snippet

{ “Name”: “DocAPITest”, “ValueScope”: “Global”, “ValueType”: “Text”, “StringValue”: “An asset added through an API call” }

I tried to add header with OrganizationUnitId to be more specific where I’m trying to create asset

Snippet

request.Headers.Add(“OrganizationUnitId”, “18”);

I do receive error 403 Forbidden
I’m administrator in that given tenant

My assumption is that I’m failing to specify tenant/OrganizationUnitId in proper way.

Thank you for hel