为Token Google Api交换授权代码的问题

我已经检查了每件事反复,似乎没有任何问题,在代码或逻辑。

代码如下:

var content = new FormUrlEncodedContent(new Dictionary<string, string>
{
    {"grant_type", "authorization_code"},
    {"code", code},
    {"redirect_uri", redirectUri.ToString()},
    {"client_id", clientId},
    {"client_secret", clientSecret}
});
    string token = string.Empty;


    using (var client = new HttpClient())
    {
        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/x-www-form-urlencoded"));
        var response = client.PostAsync(tokenEndpoint, content);
        var responseContent = response.Result.Content.ReadAsStringAsync();
        token = responseContent.ToString();
        if (!response.Result.IsSuccessStatusCode) ;
    }

    return token;

我得到了一个错误:

"error": "redirect_uri_mismatch",
"error_description": "Bad Request"

以上页面的Url为: http://localhost:62188/dashboard/googleSync.aspx

在Google控制台中,我将此Url作为授权返回Url:

那我还缺什么?