Extract custom message from 401 Unauthorized response

How do I extract my custom message from the API 401 response?

I return Unauthorized in the API:

return Unauthorized("my custom message");

In my client winform app I want to show my custom message, but the message I get from the API is "Response status code does not indicate success: 401 (Unauthorized)."

Is it possible to extract my message?

Using something like this example: HttpResponseMessage Class

// HttpClient is intended to be instantiated once per application, rather than per-use. See Remarks.
static readonly HttpClient client = new HttpClient();

static async Task Main()
{
    // Call asynchronous network methods in a try/catch block to handle exceptions.
    try
    {
        using HttpResponseMessage response = await client.GetAsync("http://www.contoso.com/");
        response.EnsureSuccessStatusCode();
        string responseBody = await response.Content.ReadAsStringAsync();
        // Above three lines can be replaced with new helper method below
        // string responseBody = await client.GetStringAsync(uri);

        Console.WriteLine(responseBody);
    }
    catch (HttpRequestException e)
    {
        Console.WriteLine("\nException Caught!");
        Console.WriteLine("Message :{0} ", e.Message);
    }
}

Yoou can extract your message from the response body:

// Extract your message from the response body
string responseBody = response.Content.ReadAsStringAsync().Result;

This is what I did -

var response = httpClient.PostAsync(url, hc).Result;
string responseBody = response.Content.ReadAsStringAsync().Result;
if (response.StatusCode != HttpStatusCode.OK)
{
  throw new Exception(response.StatusCode + " - " + responseBody);
}

Now I get my custom error from the API.