我是否需要远程登录才能通过php脚本从MySQL数据库读取和写入？

I am practicing creating an authentication system using Java, PHP, and SQL. I have one entry in the MySQL database, but my application refuses to sign in. I also created a register side of the application but it doesn't work either. So I was wondering if not having remote login access would affect it.

if ($_SERVER['REQUEST_METHOD']=='POST') {

$matriculation_number = $_POST['matriculation_number'];
$password = $_POST['password'];

$conn = mysqli_connect("localhost", "id4922470_public", "password", "id4922470_cuc_general");

if ($conn = mysqli_connect("localhost", "id4922470_public", "password", "id4922470_cuc_general")) {
    $sql = "SELECT * FROM users_general WHERE matriculation_number='$matriculation_number' ";

    $response = mysqli_query($conn, $sql);
    $check = array();
    $result = array();
    $check['connection'] = array();
    $result['login'] = array();

    if ( mysqli_num_rows($response) === 1 ) {

        $row = mysqli_fetch_assoc($response);

        if ( password_verify($password, $row['password']) ) {

            $index['matriculation_number'] = $row['matriculation_number'];
            $index['first_name'] = $row['first_name'];
            $index['middle_name'] = $row['middle_name'];
            $index['last_name'] = $row['last_name'];
            $index['gender'] = $row['gender'];
            $index['level'] = $row['level'];
            $index['programme'] = $row['programme'];
            $index['department'] = $row['department'];
            $index['college'] = $row['college'];

            array_push($result['login'], $index);

            $result['success'] = "1";
            $result['message'] = "success";
            echo json_encode($result);

            mysqli_close($conn);

        } else {

            $result['success'] = "0";
            $result['message'] = "error";
            echo json_encode($result);

            mysqli_close($conn);

        }

    } else {
        $check['Connected'] = "Connection failed";
        echo json_encode($check);
    }
}
}

The volley code:

StringRequest stringRequest = new StringRequest(Request.Method.POST, LOGIN_REQUEST_URL,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    try {
                        System.err.println("__________________________________________LOG________________________________________");
                        Log.i("tagconvertstr", "["+response+"]");
                        System.err.println("__________________________________________LOG________________________________________");
                        JSONObject jsonObject = new JSONObject(response);
                        String success = jsonObject.getString("success");
                        JSONArray jsonArray = jsonObject.getJSONArray("login");

                        if (success.equals("1")) {
                            for (int i = 0; i < jsonArray.length(); i++) {
                                JSONObject object = jsonArray.getJSONObject(i);

                                String matriculation_number = object.getString("matriculation_number").trim();
                                String first_name = object.getString("first_name").trim();
                                String middle_name = object.getString("middle_name").trim();
                                String last_name = object.getString("last_name").trim();
                                String gender = object.getString("gender").trim();
                                int level = object.getInt("level");
                                String programme = object.getString("programme").trim();
                                String department = object.getString("department").trim();
                                String college = object.getString("college").trim();

                                System.out.println(matriculation_number + "
" + first_name + "
" + middle_name + "
" +
                                last_name + "
" + gender + "
" + level + "
" + programme + "
" +department + "
" + college);
                                System.out.println("___________________________CHECK___________________________________");

                                String message = "Welcome " + matriculation_number;
                                Toast.makeText(LoginActivity.this, message, Toast.LENGTH_SHORT).show();

                                Intent l = new Intent(LoginActivity.this, DashboardActivity.class);
                                startActivity(l);
                                LoginActivity.this.finish();
                            }
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                        String message = "Error " + e.toString();
                        Toast.makeText(LoginActivity.this, message, Toast.LENGTH_SHORT).show();
                        pWord.setText("");
                        pWord.clearFocus();
                        uName.clearFocus();
                        login.setVisibility(View.VISIBLE);
                    }
                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    String message = "Error " + error.toString();
                    Toast.makeText(LoginActivity.this, message, Toast.LENGTH_SHORT).show();
                    pWord.setText("");
                    pWord.clearFocus();
                    uName.clearFocus();
                    login.setVisibility(View.VISIBLE);
                }
            }
    ) {
        @Override
        protected Map<String, String> getParams() throws AuthFailureError {
            Map<String, String> params = new HashMap<>();
            params.put("matriculation_number", matriculation_number);
            params.put("password", password);
            return params;
        }
    };

    RequestQueue requestQueue = Volley.newRequestQueue(this);
    requestQueue.add(stringRequest);
}

I was asked to post the script... which I have done. I have also added a check to make sure the script is connected to the database.