context Identity is not set in AuthorizationHandler

Hello!

I am using policy based authorization. Here is what I have in my Startup.cs:

services.AddSingleton<IAuthorizationHandler, PrivateAuthorizationHandler>();
services.AddAuthorization(options =>
{
   options.AddPolicy("User", policy => policy.Requirements.Add(new PrivateRequirement(new[] {1}, "User")));
   options.AddPolicy("Super User", policy => policy.Requirements.Add(new PrivateRequirement(new[] {1, 2}, "Super User")));
   options.AddPolicy("Admin", policy => policy.Requirements.Add(new PrivateRequirement(new[] {1, 2, 3}, "Admin")));
});

My handler looks like that:

protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, PrivateRequirement requirement)
        {
            try
            {
                var ntName = context.User.Identity.Name; // <= always empty string ""
                if (string.IsNullOrWhiteSpace(ntName))
                {
                    context.Fail(); // <= always getting here
                }
                else
                {
                      //check requirement
                }
            }
            catch (Exception ex)
            {
                context.Fail();
            }

            return Task.CompletedTask;
        }

I am using Windows Authentication. Locally it is working fine. When I deploy the project to IIS, I am getting the issue above. It is like context is not being passed to the handler correctly.

Any idea on how to get Authenticated User in a handler?

Thank you!