当我尝试调用API时获得401-Unauthorized

Question

我正在访问需要授权令牌的外部Api呼叫 我的代码看起来像

HttpClient client = new HttpClient();
string baseUrl = "http://url/organizations/d5d6553e-6bb2-4081-87e2-353e80f47d6f/users.json";
client.BaseAddress = new Uri(baseUrl);

// Add an Accept header for JSON format.
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
client.DefaultRequestHeaders.Add("Authorization", "Basic TFVBV0dkeFZlSklJZ0hjajM0M0I6");

HttpResponseMessage response = client.GetAsync(baseUrl).Result;

请让我知道该怎么做