I see you are using .NET Core.
.NET Core is hosted in Kestrel instead of the normal IIS and does not support windows authentication. Although you can use HTTP.sys which is a web server implementation in .NET Core and does support windows authentication.
The below code configures the app's web host to use HTTP.sys with Windows authentication.
public class Program
{
public static void Main(string[] args) =>
BuildWebHost(args).Run();
public static IWebHost BuildWebHost(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.UseStartup<Startup>()
.UseHttpSys(options =>
{
options.Authentication.Schemes =
AuthenticationSchemes.NTLM | AuthenticationSchemes.Negotiate;
options.Authentication.AllowAnonymous = false;
})
.Build();
}
the article explaining this code is here