c# 对网页的代理请求返回错误？

Question

I am trying to code an application which allows me to login into my Netflix account and I am trying to manage some data from there. Now my request works when using it without a proxy. I successfully get redirected to the netflix/browse page where I can select a user profile. But when using a http proxy it returns a webpage which shows that the password is invalid. Now my question is how to fix this? I have googled a bit but did not really find anything so I hope someone can help me here. I can only assume its something with the proxy but I really dont know.

Picture of request with proxy even tho the password is correct: https://imgur.com/a/GtmfI76

With proxy --> does not work

Without proxy --> works

Here is my code that I use

        string urlGet = "https://www.netflix.com";
        string urlPost = "https://www.netflix.com/login";
        string username = "myemail";
        string password = "mypassword";
        string proxy = "219.147.112.150:1080"; // this is an example proxy but the normal ones work for sure

        var cookieContainer = new CookieContainer();
        var httpclientHandler = new HttpClientHandler();
        httpclientHandler.CookieContainer = cookieContainer;
        httpclientHandler.Proxy = new WebProxy(proxy);
        httpclientHandler.UseProxy = true;
        httpclientHandler.UseDefaultCredentials = true;

        var httpClient = new HttpClient(httpclientHandler);
        var result = await httpClient.GetAsync(urlGet);
      
        string resultString = "";
        Stream resultStream = await result.Content.ReadAsStreamAsync();
        using (StreamReader reader = new StreamReader(resultStream))
        {
            string line;
            while ((line = reader.ReadLine()) != null)
            {
                resultString += line;
            }
        }

        List<Cookie> cookies = cookieContainer.GetCookies(new Uri(urlGet)).Cast<Cookie>().ToList();

        string authURL = Regex.Match(resultString, @"(?<=""authURL"":"")(.*?)(?="")").Value.Replace(@"\x3D", "=").Replace(@"\x2F", "/").Replace(@"\x2B", "+");

        var content = new System.Net.Http.FormUrlEncodedContent(new[]
        {
            new KeyValuePair<string, string>("userLoginId", username),
            new KeyValuePair<string, string>("password", password),
            new KeyValuePair<string, string>("rememberMe", "false"),
            new KeyValuePair<string, string>("flow", "websiteSignUp"),
            new KeyValuePair<string, string>("mode", "login"),
            new KeyValuePair<string, string>("action", "loginAction"),
            new KeyValuePair<string, string>("withFields", "rememberMe,nextPage,userLoginId,password,countryCode,countryIsoCode,recaptchaResponseToken,recaptchaError,recaptchaResponseTime"),
            new KeyValuePair<string, string>("authURL", authURL),
        });
        // settings for httpclient

        httpClient.DefaultRequestHeaders.Host = "www.netflix.com";
        httpClient.DefaultRequestHeaders.AcceptLanguage.ParseAdd("en-US;q=0.8,en;q=0.7");
        httpClient.DefaultRequestHeaders.Accept.ParseAdd("text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9");
        httpClient.DefaultRequestHeaders.UserAgent.ParseAdd(userAgent);

        var resultPOST = await httpClient.PostAsync(new Uri(urlPost), content);
        string resultPOSTString = "";
        Stream resultPOSTStream = await resultPOST.Content.ReadAsStreamAsync();
        using (StreamReader reader = new StreamReader(resultPOSTStream))
        {
            resultPOSTString = reader.ReadToEnd();
        }
       
        if (resultPOSTString.Contains("/browse") || resultPOSTString.Contains("/signup"))
        {
            File.WriteAllText(@"C:\Users\PC3221\Desktop\postrq.html", resultPOSTString); // THIS WORKS WITHOUT PROXY AND RETURNS GOOD RESULT
            Console.WriteLine("Done! Logged in");

        }
        else
        {
            Console.WriteLine("Tried password but failed!");
            File.WriteAllText(@"C:\Users\PC3221\Desktop\postrqNotWorking.html", resultPOSTString); // THIS IS THE RESULT WITH PROXY AND RETURNS THE IMAGE I POSTED AT THE TOP
        }

Answer 1

I won't suspect that VPN/Proxy in blacklist IP-based are allowed to connect to Netflix, according to Netflix FAQ https://help.netflix.com/en/node/277

Do you use a VPN or proxy for work or for privacy?

A VPN or proxy may prevent you from streaming content that isn't available globally. Disable any VPN or proxy and try Netflix again.

The best test method in this case is using that VPN/Proxy to connect via Browser to make sure it does. Then we could affirm that VPN/Proxy has been blocked and the message is just wrong context

Although they have several workaround ways to detect VPN/Proxy, but IP-based list is not always up-to-date, therefore you might try some other VPN IPs in your country to test via Browser first, perhaps successfully rate could grow up