Sketchfab Upload using c# .net

SketchfabUpload.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Threading.Tasks;

namespace Test
{
    public static class FormUpload
    {
        private static readonly Encoding encoding = Encoding.UTF8;
        public static HttpWebResponse MultipartFormDataPost(string postUrl,
                                                            string userAgent, Dictionary<string, object> postParameters)
        {
            string formDataBoundary = String.Format("----------{0:N}",
                                                    Guid.NewGuid());
            string contentType = "multipart/form-data; boundary=" +
                formDataBoundary;

            byte[] formData = GetMultipartFormData(postParameters,
                                                   formDataBoundary);

            return PostForm(postUrl, userAgent, contentType, formData);
        }
        private static HttpWebResponse PostForm(string postUrl, string
                                                userAgent, string contentType, byte[] formData)
        {
            HttpWebRequest request = WebRequest.Create(postUrl) as
                HttpWebRequest;

            if (request == null)
            {
                throw new NullReferenceException("request is not a http
request");
            }

// Set up the request properties.
            request.Method = "POST";
            request.ContentType = contentType;
            request.UserAgent = userAgent;
            request.CookieContainer = new CookieContainer();
            request.ContentLength = formData.Length;

// You could add authentication here as well if needed:
// request.PreAuthenticate = true;
// request.AuthenticationLevel =
            System.Net.Security.AuthenticationLevel.MutualAuthRequested;
// request.Headers.Add("Authorization", "Basic " +
            Convert.ToBase64String(System.Text.Encoding.Default.GetBytes("username" +
                                                                         ":" + "password")));

// Send the form data to the request.
        using (Stream requestStream = request.GetRequestStream())
        {
            requestStream.Write(formData, 0, formData.Length);
            requestStream.Close();
        }

        return request.GetResponse() as HttpWebResponse;
    }

    private static byte[] GetMultipartFormData(Dictionary<string,
                                               object> postParameters, string boundary)
    {
        Stream formDataStream = new System.IO.MemoryStream();
        bool needsCLRF = false;

        foreach (var param in postParameters)
        {
// Thanks to feedback from commenters, add a CRLF to allow
            multiple parameters to be added.
// Skip it on the first parameter, add it to subsequent
                parameters.
                if (needsCLRF)
                    formDataStream.Write(encoding.GetBytes("\r\n"), 0,
                                         encoding.GetByteCount("\r\n"));

            needsCLRF = true;

            if (param.Value is FileParameter)
            {
                FileParameter fileToUpload = (FileParameter)param.Value;

// Add just the first part of this param, since we will
                write the file data directly to the Stream
                    string header =
                    string.Format("--{0}\r\nContent-Disposition: form-data; name=\"{1}\";
filename=\"{2}\"\r\nContent-Type: {3}\r\n\r\n",
                                  boundary,
                                  param.Key,
                                  fileToUpload.FileName ?? param.Key,
                                  fileToUpload.ContentType ??
                                  "application/octet-stream");

                formDataStream.Write(encoding.GetBytes(header), 0,
                                     encoding.GetByteCount(header));

// Write the file data directly to the Stream, rather
                than serializing it to a string.
                    formDataStream.Write(fileToUpload.File, 0,
                                         fileToUpload.File.Length);
            }
            else
            {
                string postData =
                    string.Format("--{0}\r\nContent-Disposition: form-data;
name=\"{1}\"\r\n\r\n{2}",
                                  boundary,
                                  param.Key,
                                  param.Value);
                formDataStream.Write(encoding.GetBytes(postData), 0,
                                     encoding.GetByteCount(postData));
            }
        }

// Add the end of the request. Start with a newline
        string footer = "\r\n--" + boundary + "--\r\n";
        formDataStream.Write(encoding.GetBytes(footer), 0,
                             encoding.GetByteCount(footer));

// Dump the Stream into a byte[]
        formDataStream.Position = 0;
        byte[] formData = new byte[formDataStream.Length];
        formDataStream.Read(formData, 0, formData.Length);
        formDataStream.Close();

        return formData;
    }

    public class FileParameter
    {
        public byte[] File { get; set; }
        public string FileName { get; set; }
        public string ContentType { get; set; }
        public FileParameter(byte[] file) : this(file, null) { }
        public FileParameter(byte[] file, string filename) : this(file,
                                                                  filename, null) { }
        public FileParameter(byte[] file, string filename, string
                             contenttype)
        {
            File = file;
            FileName = filename;
            ContentType = contenttype;
        }
    }
}

public class Program
{
    public static void Main(string[] args)
    {
// Read file data
        FileStream fs = new FileStream("c:\\Exports.zip",
                                       FileMode.Open, FileAccess.Read);
        byte[] data = new byte[fs.Length];
        fs.Read(data, 0, data.Length);
        fs.Close();

// Generate post objects
        Dictionary<string, object> postParameters = new Dictionary<string,
            object>();
        postParameters.Add("token", "**mytoken***");
        postParameters.Add("name", "mymodeltitle");
        postParameters.Add("modelFile", new FormUpload.FileParameter(data,
                                                                     "Exports.zip", "application/zip"));

// Create request and receive response
        string postURL = "https://api.sketchfab.com/v2/models";
        string userAgent = "Someone";
        HttpWebResponse webResponse = FormUpload.MultipartFormDataPost(postURL,
                                                                       userAgent, postParameters);

// Process response
        StreamReader responseReader = new
            StreamReader(webResponse.GetResponseStream());
        string fullResponse = responseReader.ReadToEnd();
        webResponse.Close();
//Response.Write(fullResponse);
    }
}
}

This code is valid even for the newest version of the api the version 3 (https://api.sketchfab.com/v3/models) ? I'm asking becuase i receveid the error 401 from the server like it is a non valid operation.