Username       :        EBA
Token          :       34242353453456563DSFS

public GsonRequest(int method, String url, Class<T> responseClass,
                       Map<String, String> parameters, Map<String, String> headers, Listener<T> listener,
                       ErrorListener errorListener) {
        super(method, url, errorListener);
        this.mListener = listener;
        this.mResponseClass = responseClass;
        this.mParameters = parameters;
        this.mHeaders = headers;
    }

    /**
     * Header getter method
     *
     * @return
     * @throws AuthFailureError
     */
    @Override
    public Map<String, String> getHeaders() throws AuthFailureError {
        return mHeaders != null ? mHeaders : super.getHeaders();
    }

StringRequest stringRequest = new StringRequest(Request.Method.POST, "https://www.yourserver.com/get_auth.php",
new Response.Listener<String>()
{
    @Override
    public void onResponse(String response)
    {
        serverResponse = response;

        // get response string here; if successful

        Toast.makeText(getActivity(),response,Toast.LENGTH_LONG).show();
    }
},
new Response.ErrorListener()
{
    @Override
    public void onErrorResponse(VolleyError error)
    {
        serverResponse = error.toString();

        // If request could not be placed then error report here

        Toast.makeText(getActivity(),error.toString(),Toast.LENGTH_LONG).show();
    }
})

{
@Override
protected Map<String,String> getParams()
{
    Map<String,String> params = new HashMap<String, String>();
    params.put("Username",FirstLast);
    params.put("Token",EmailField.getText().toString());
    return params;
}};

RequestQueue requestQueue = Volley.newRequestQueue(getActivity());
requestQueue.add(stringRequest);

<?php
if($_SERVER['REQUEST_METHOD']=='POST')
{
    $UserInput = $_POST['Username'];
    $UserId = $_POST['Token'];

    $con = mysqli_connect("localhost", "id4859061_instapromo", "sandhya12345","id4859061_instapromo");

    if (!$con)
    {
        echo "EXCEPTION_CODE_1";
        exit();
    }

    $result = $con->query("SELECT * FROM USERS WHERE `DEVID` = '$UserId' AND `KEYGEN` = '$UserInput'");

    if (!$result)
    {
        echo "EXCEPTION_CODE_2";
        exit();
    }
    if ($result->num_rows == 0)
    {
        echo "FAILURE";
        exit();
    }
    if ($result->num_rows == 1)
    {
        $row = $result->fetch_assoc();
        $TempThisDate = $row["VALUEDATE"];

        $InstDate = DateTime::createFromFormat('d/m/Y',$TempThisDate);
        $InstallDate = $InstDate->format('d-m-Y');

        $Response = "SUCCESS#".$InstallDate;
        echo $Response;
        exit();
    }
    if ($result->num_rows > 1)
    {
        echo "REDUNDANT_RECORDS_FOUND";
        exit();
    }

}
else
{
   echo "EXCEPTION_CODE_3";
}