登录Nike网站时持续出现403 Forbidden错误求助（附C#代码）

我尝试登录Nike网站时，尽管登录凭证正确（出于安全考虑已替换示例账号密码，报错时所用凭证无误），却持续收到403 Forbidden错误。我推测操作存在问题但无法定位，附上相关C#请求代码，恳请技术帮助。

using System;
using System.Text;
using System.Threading.Tasks;

namespace Project007
{
    public class Program
    {
        static async Task Main(string[] args)
        {
            LoginClient loginClient = new LoginClient();
            await loginClient.Put();
            while (true)
            {
                Console.ReadKey();
            }
        }
        
    }
    public class LoginClient
    {
        private readonly HttpClient _client;

        public LoginClient()
        {
            _client = new HttpClient();
        }

        public async Task Put()
        {
            using (var request = new HttpRequestMessage(HttpMethod.Post, $"https://accounts.nike.com/challenge/password/v1"))
            {
                request.Content = new StringContent("{credential: \"example@gmail.com\", password: \"example\"}", Encoding.UTF8, "application/json");
                request.Headers.Add("user-agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.0.0 Safari/537.36");
                using (var response = await _client.SendAsync(request))
                {
                    Console.WriteLine(response.StatusCode);
                }
            }
        }
    }
}

内容的提问来源于stack exchange，提问作者hud Kad