操作会跳过返回块，然后重定向到错误页面

Question

ASP.NET Core 2.0;发送GET请求（HttpClient）后，我的程序跳过代码中的返回块，并将当前操作重定向到Error页面，而不会捕获异常。您可以在线观看有问题的视频或下载here 对视频中的音乐感到抱歉！

    public IActionResult VKAuth()
    {
        bool ok = Request.Query.TryGetValue("code", out var value);
        if (!ok)
            return RedirectToActionPermanent("Error");
        else // ok == true, go here
        {
            try
            {
                GetAccessToken(value).Wait(); // it's ok
                return RedirectToActionPermanent("Deleting"); // skips this return block
            }
            catch
            {
                return RedirectToActionPermanent("Error");
            }
        }
    } // then program stops here and then next step is error action of controller

    private async Task GetAccessToken(string value)
    {
        string Json;
        using (var handler = new HttpClientHandler() { ClientCertificateOptions = ClientCertificateOption.Manual, SslProtocols = SslProtocols.Tls|SslProtocols.Tls11|SslProtocols.Tls12 })
            using (HttpClient Client = new HttpClient(handler) { BaseAddress = new System.Uri("https://oauth.vk.com/") })
                Json = await Client.GetStringAsync($"access_token?client_id={ClientId}&client_secret={ClientSecret}&redirect_uri={Domain}/{AuthRoute}&code=" + value);
        JsonTokenResponseModel TokenModel = JsonConvert.DeserializeObject<JsonTokenResponseModel>(Json);
        AccessToken = new UserAccessToken(TokenModel.access_token, TokenModel.expires_in);
    }

更新

    public IActionResult Deleting()
    {
        VKChange();
        return View();
    }

    private async void VKChange()
    {
        try
        {
            await ClearPage();
            Response.Redirect(Url.Action("Success", "SocialSuicide"), true);
        }
        catch
        {
            Response.Redirect(Url.Action("Error", "SocialSuicide"), true);
        }
    }

更新2：

    public IActionResult Deleting()
    {
        Request.Cookies.TryGetValue("code", out string code);
        ViewData["Token"] = "https://oauth.vk.com/" + $"access_token?client_id={ClientId}&client_secret={ClientSecret}&redirect_uri={Domain}/{AuthRoute}&code=" + code;
        ViewData["WallScript"] = Method($"execute?code={ExecuteWallScript}");
        ViewData["ApiVersion"] = ApiVersion;
        return View();
    }

    public IActionResult VKAuth()
    {
        bool ok = Request.Query.TryGetValue("code", out var value);
        if (!ok)
            return RedirectToActionPermanent("Error");
        else
        {
            Response.Cookies.Append("code", value);
            return RedirectToActionPermanent("Deleting", "SocialSuicide");
        }
    }

我还有问题，我删除了所有异步方法。