Getting Cookie with Flurl 3.0

Question

I need to call an endpoint to perform and retrieve 3 cookies to call another application's endpoint, and I'm using flurl 3.0 to perform the call. The login is successful, but the cookie session is always empty. If I perform the call with Postman, I see the cookies and call the other endpoint. This is the code I'm using:

        var loginData = new
        {
            lt = GetLoginTicket(),
            username = _enConfig.Username,
            password = _enConfig.Password
        };


        using var session = new CookieSession(loginUrl);
        {
            var login = await session.Request(loginUrl).AllowAnyHttpStatus().PostUrlEncodedAsync(loginData);
            _jar = login.ResponseMessage.IsSuccessStatusCode ? session.Cookies : null;
        }

The documentation of the application says this:

The response code can be:

302, a redirection The authentication is successful. An SSO cookie (also named ######) is sent in the response header.

I get the 302 Status Code and in the body, I get the correct HTML page, but the cookies are always empty.

Am I missing something?

EDIT: I've modified the code as follows to have the Cookies. I almost solved my problem. Still, 1 cookie is missing after the post with the Url encoded body. The code is now:

  using var session = new CookieSession(_enConfig.PassportBaseEndpoint);
            {

                _logger.LogInformation("Getting login ticket");

                var ltData = new LoginTicket();
                var ltResponse = await session.Request("/login?action=get_auth_params").GetAsync();
                if (ltResponse.ResponseMessage.IsSuccessStatusCode)
                {

                    var ltString = await ltResponse.ResponseMessage.Content.ReadAsStringAsync();
                    ltData = JsonConvert.DeserializeObject<LoginTicket>(ltString);
                    
                    if (ltData == null || string.IsNullOrEmpty(ltData.Lt))
                        throw new Exception("Could not deserialize login token");  
                }
                else
                    throw new Exception("Could not get Login Ticket from enovia");

                var loginData = new
                {
                    lt = ltData.Lt,
                    username = _enConfig.Username,
                    password = _enConfig.Password
                };

                var login = await session.Request("/login/").AllowAnyHttpStatus().PostUrlEncodedAsync(loginData);
         
                _jar = login.ResponseMessage.IsSuccessStatusCode ? session.Cookies : null;
 
            }

After the first GET call to retrieve the login Ticket, I also get 2 cookies with a SessionID. When I perform the POST, I must also pass these cookies to have a successful login. In the response, I should get 1 more cookie with a token. The problem now is that the login is successful, but I don't get the third cookie in the session or the login response.

EDIT 2: Without Flurl I'm able to get the cookies with this code

        CookieContainer cookies = new CookieContainer();
        HttpClientHandler handler = new HttpClientHandler();
        handler.CookieContainer = cookies;
        handler.ServerCertificateCustomValidationCallback = (a, b, c, d) => true;
        var client = new HttpClient(handler);
        var response = client.GetAsync($"{_enConfig.PassportBaseEndpoint}/login?action=get_auth_params").Result;
        var loginTicket = JsonConvert.DeserializeObject<LoginTicket>(await response.Content.ReadAsStringAsync());
        var loginBody = new Dictionary<string, string>();
        loginBody.Add("lt", loginTicket.Lt);
        loginBody.Add("username", _enConfig.Username);
        loginBody.Add("password", _enConfig.Password);

        var encodedContent = new FormUrlEncodedContent(loginBody);
        response = await client.PostAsync($"{_enConfig.PassportBaseEndpoint}/login", encodedContent);

        _logger.LogInformation(await response.Content.ReadAsStringAsync());
        Uri uri = new Uri($"{_enConfig.PassportBaseEndpoint}/login");
        IEnumerable<Cookie> responseCookies = cookies.GetCookies(uri).Cast<Cookie>();
        foreach (Cookie cookie in responseCookies)
            Console.WriteLine(cookie.Name + ": " + cookie.Value);