Cornerstone lms CSOD未授权异常：检查您的凭据

正在尝试访问员工列表，但收到此错误消息

CSOD未授权异常：检查您的凭据

        var client = new RestClient("https://xxx.csod.com/services/api/x/users/v1/employees");
        var request = new RestRequest(Method.POST);
        request.AddHeader("cache-control", "no-cache");
        request.AddHeader("content-type", "application/x-www-form-urlencoded");
        request.AddParameter("application/x-www-form-urlencoded", "grant_type=client_credentials&client_id=xxx&client_secret=xxx", ParameterType.RequestBody);
        IRestResponse response = client.Execute(request);

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我的帐户具有编辑和查看员工API的权限。还有什么问题。

我的接入点错误：

var client = new RestClient("https://xxx.csod.com/services/api/oauth2/token");

using Newtonsoft.Json.Linq;
using RestSharp;
using System;

namespace TestAPI
{
    class Program
    {
        static void Main(string[] args)
        {
            String id = "xxx";
            String secret = "xxx";

            var client = new RestClient("https://xxx.csod.com/services/api/oauth2/token");
            var request = new RestRequest(Method.POST);
            request.AddHeader("cache-control", "no-cache");
            request.AddHeader("content-type", "application/x-www-form-urlencoded");
            request.AddParameter("application/x-www-form-urlencoded", "grant_type=client_credentials&scope=all&client_id=" + id + "&client_secret=" + secret, ParameterType.RequestBody);
            IRestResponse response = client.Execute(request);

            dynamic resp = JObject.Parse(response.Content);
            String token = resp.access_token;            

            client = new RestClient("https://xxx.csod.com/services/api/x/users/v1/employees");
            request = new RestRequest(Method.GET);
            request.AddHeader("authorization", "Bearer " + token);
            request.AddHeader("cache-control", "no-cache");
            response = client.Execute(request);
        }        
    }
}

---

我使用了错误的接入点：

var client = new RestClient("https://xxx.csod.com/services/api/oauth2/token");

using Newtonsoft.Json.Linq;
using RestSharp;
using System;

namespace TestAPI
{
    class Program
    {
        static void Main(string[] args)
        {
            String id = "xxx";
            String secret = "xxx";

            var client = new RestClient("https://xxx.csod.com/services/api/oauth2/token");
            var request = new RestRequest(Method.POST);
            request.AddHeader("cache-control", "no-cache");
            request.AddHeader("content-type", "application/x-www-form-urlencoded");
            request.AddParameter("application/x-www-form-urlencoded", "grant_type=client_credentials&scope=all&client_id=" + id + "&client_secret=" + secret, ParameterType.RequestBody);
            IRestResponse response = client.Execute(request);

            dynamic resp = JObject.Parse(response.Content);
            String token = resp.access_token;            

            client = new RestClient("https://xxx.csod.com/services/api/x/users/v1/employees");
            request = new RestRequest(Method.GET);
            request.AddHeader("authorization", "Bearer " + token);
            request.AddHeader("cache-control", "no-cache");
            response = client.Execute(request);
        }        
    }
}