RestClient Client = new RestClient(Settings.Url)
            {
                UserAgent = Settings.UserAgent,
                FollowRedirects = false
            };

            RestRequest Req = new RestRequest(Method.POST);
            Req.AddHeader("Content-Type", Settings.ContentType);
            Req.AddHeader("Accept", "application/json, text/plain, */*");
            Req.AddHeader("Accept-Encoding", "gzip, deflate, br");
            Req.AddHeader("Accept-Language", "en-US,en;q=0.9");

            Req.AddHeader("Referer", Settings.Referer);

            Req.AddParameter("remember=false&username=xxx&password=xxx&captcha_token=&csrf_token=", ParameterType.RequestBody);
            Client.ExecuteAsync(Req, response =>
            {
                if (response.StatusCode == HttpStatusCode.BadRequest)
                {
                    Console.WriteLine("Access DENIED!", Color.DarkRed);
                }
                else
                {
                    Console.WriteLine("Accessed.", Color.Green);
                }
            });

public class Settings
{
    public static string Url = "https://accounts.spotify.com/api/login";
    public static string Referer = "https://accounts.spotify.com/en/login/";
    public static string UserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.102 Safari/537.36";
    public static string ContentType = "application/x-www-form-urlencoded";
}