Android Volley Post StringRequest ServerError

Question

我正在尝试将我的应用程序与在POSTMAN中正常运行的API连接，但不能在我的Android APP中运行。

这是我的代码。我的设备上有互联网许可和互联网。网址和参数也很好。

void loginTask()
{

    RequestQueue queue = Volley.newRequestQueue(this);
    String url = URLS.url_login;
    pd = new ProgressDialog(LoginActivity.this);
    pd.setMessage("Ingresando");
    pd.show();
    app.L("url : "+url);

    StringRequest postRequest = new StringRequest(Request.Method.POST, url,
            new Response.Listener<String>()
            {
                @Override
                public void onResponse(String response)
                {
                    app.L(response);

                }
            },
            new Response.ErrorListener()
            {
                @Override
                public void onErrorResponse(VolleyError error)
                {
                    pd.dismiss();
                    error.printStackTrace();
                    app.LE("error => "+error.toString());
                }
            }
    ) {

        public String getBodyContentType()
        {
            return "application/json";
        }


        @Override
        public Map<String, String> getHeaders() throws AuthFailureError {
            Map<String, String> params = new HashMap<String, String>();
            params.put("Content-Type", "application/json");
            return params;
        }


        // this is the relevant method
        @Override
        public byte[] getBody()
        {
            return getJSONBody().toString().getBytes();
        }
    };
    queue.add(postRequest);


}

private String getJSONBody()
{
    JSONObject body = null;
    try
    {
        body = new JSONObject();
        body.put(URLS.param_username,editText_user.getText().toString());
        body.put(URLS.param_pass,editText_pass.getText().toString());
    }
    catch (Exception ex)
    {
        ex.printStackTrace();
    }
    return body;
}

这是错误

BasicNetwork.performRequest: Unexpected response code 404 for http://200.51.42.196:11440/stocktaller/public_html/client/login

com.android.volley.ServerError
 at com.android.volley.toolbox.BasicNetwork.performRequest(BasicNetwork.java:163)
at com.android.volley.NetworkDispatcher.run(NetworkDispatcher.java:112)

有任何帮助吗？非常感谢！我会尝试其他解决方案

更新：我尝试使用相同结果的JSONRequest

JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.POST, url, getJSONBody(), new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response)
            {
                pd.dismiss();
                app.L(response.toString());
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error)
            {
                pd.dismiss();
                error.printStackTrace();
                app.LE("error => "+error.toString());
            }
        })
        {
            public String getBodyContentType()
            {
                return "application/json";
            }


            @Override
            public Map<String, String> getHeaders() throws AuthFailureError {
                Map<String, String> params = new HashMap<String, String>();
                params.put("Content-Type", "application/json");
                return params;
            }
        };
        queue.add(jsonObjectRequest);