Error 403 - access forbidden in password validation with Mysql in PHP7 code, how to fix?

<?php

/**
 * A simple, clean and secure PHP Login Script / MINIMAL VERSION
 *
 * Uses PHP SESSIONS, modern password-hashing and salting and gives the basic functions a proper login system needs.
 *
 * @author Panique
 * @link https://github.com/panique/php-login-minimal/
 * @license http://opensource.org/licenses/MIT MIT License
 */

// checking for minimum PHP version
if (version_compare(PHP_VERSION, '5.3.7', '<')) {
    exit("Sorry, Simple PHP Login does not run on a PHP version smaller than 5.3.7 !");
} else if (version_compare(PHP_VERSION, '5.5.0', '<')) {
    // if you are using PHP 5.3 or PHP 5.4 you have to include the password_api_compatibility_library.php
    // (this library adds the PHP 5.5 password hashing functions to older versions of PHP)
    require_once("libraries/password_compatibility_library.php");
}

// include the configs / constants for the database connection
require_once("config/db.php");

// load the login class
require_once("classes/Login.php");

// create a login object. when this object is created, it will do all login/logout stuff automatically
// so this single line handles the entire login process. in consequence, you can simply ...
$login = new Login();

// ... ask if we are logged in here:
if ($login->isUserLoggedIn() == true) {
    // the user is logged in. you can do whatever you want here.
    // for demonstration purposes, we simply show the "you are logged in" view.
    include("views/logged_in.php");

} else {
    // the user is not logged in. you can do whatever you want here.
    // for demonstration purposes, we simply show the "you are not logged in" view.
    include("views/not_logged_in.php");
}

<?php
// show potential errors / feedback (from registration object)
if (isset($registration)) {
    if ($registration->errors) {
        foreach ($registration->errors as $error) {
            echo $error;
        }
    }
    if ($registration->messages) {
        foreach ($registration->messages as $message) {
            echo $message;
        }
    }
}
?>

<!-- register form -->
<form method="post" action="register.php" name="registerform">

    <!-- the user name input field uses a HTML5 pattern check -->
    <label for="login_input_username">Username (only letters and numbers, 2 to 64 characters)</label>
    <input id="login_input_username" class="login_input" type="text" pattern="[a-zA-Z0-9]{2,64}" name="user_name" required />

    <!-- the email input field uses a HTML5 email type check -->
    <label for="login_input_email">User's email</label>
    <input id="login_input_email" class="login_input" type="email" name="user_email" required />

    <label for="login_input_password_new">Password (min. 6 characters)</label>
    <input id="login_input_password_new" class="login_input" type="password" name="user_password_new" pattern=".{6,}" required autocomplete="off" />

    <label for="login_input_password_repeat">Repeat password</label>
    <input id="login_input_password_repeat" class="login_input" type="password" name="user_password_repeat" pattern=".{6,}" required autocomplete="off" />
    <input type="submit"  name="register" value="Register" />

</form>

<!-- backlink -->
<a href="index.php">Back to Login Page</a>

<?php

/**
 * Class login
 * handles the user's login and logout process
 */
class Login
{
    /**
     * @var object The database connection
     */
    private $db_connection = null;
    /**
     * @var array Collection of error messages
     */
    public $errors = array();
    /**
     * @var array Collection of success / neutral messages
     */
    public $messages = array();

    /**
     * the function "__construct()" automatically starts whenever an object of this class is created,
     * you know, when you do "$login = new Login();"
     */
    public function __construct()
    {
        // create/read session, absolutely necessary
        session_start();

        // check the possible login actions:
        // if user tried to log out (happen when user clicks logout button)
        if (isset($_GET["logout"])) {
            $this->doLogout();
        }
        // login via post data (if user just submitted a login form)
        elseif (isset($_POST["login"])) {
            $this->dologinWithPostData();
        }
    }

    /**
     * log in with post data
     */
    private function dologinWithPostData()
    {
        // check login form contents
        if (empty($_POST['nome'])) {
            $this->errors[] = "Username field was empty.";
        } elseif (empty($_POST['senha'])) {
            $this->errors[] = "Password field was empty.";
        } elseif (!empty($_POST['nome']) && !empty($_POST['senha'])) {

            // create a database connection, using the constants from config/db.php (which we loaded in index.php)
            $this->db_connection = new mysqli(DB_HOST, DB_USER, DB_PASS, DB_NAME);

            // change character set to utf8 and check it
            if (!$this->db_connection->set_charset("utf8")) {
                $this->errors[] = $this->db_connection->error;
            }

            // if no connection errors (= working database connection)
            if (!$this->db_connection->connect_errno) {

                // escape the POST stuff
                $user_name = $this->db_connection->real_escape_string($_POST['nome']);

                // database query, getting all the info of the selected user (allows login via email address in the
                // username field)
                $sql = "SELECT nome, email, senha
                        FROM freitas_clientes
                        WHERE nome = '" . $user_name . "' OR email = '" . $user_name . "';";
                $result_of_login_check = $this->db_connection->query($sql);

                // if this user exists
                if ($result_of_login_check->num_rows == 1) {

                    // get result row (as an object)
                    $result_row = $result_of_login_check->fetch_object();

                    // using PHP 5.5's password_verify() function to check if the provided password fits
                    // the hash of that user's password
                    if (password_verify($_POST['senha'], $result_row->user_password_hash)) {

                        // write user data into PHP SESSION (a file on your server)
                        $_SESSION['nome'] = $result_row->user_name;
                        $_SESSION['email'] = $result_row->user_email;
                        $_SESSION['user_login_status'] = 1;

                    } else {
                        $this->errors[] = "Wrong password. Try again.";
                    }
                } else {
                    $this->errors[] = "This user does not exist.";
                }
            } else {
                $this->errors[] = "Database connection problem.";
            }
        }
    }

    /**
     * perform the logout
     */
    public function doLogout()
    {
        // delete the session of the user
        $_SESSION = array();
        session_destroy();
        // return a little feeedback message
        $this->messages[] = "You have been logged out.";

    }

    /**
     * simply return the current state of the user's login
     * @return boolean user's login status
     */
    public function isUserLoggedIn()
    {
        if (isset($_SESSION['user_login_status']) AND $_SESSION['user_login_status'] == 1) {
            return true;
        }
        // default return
        return false;
    }
}

<?php

/**
 * Configuration for: Database Connection
 *
 * For more information about constants please @see http://php.net/manual/en/function.define.php
 * If you want to know why we use "define" instead of "const" @see http://stackoverflow.com/q/2447791/1114320
 *
 * DB_HOST: database host, usually it's "127.0.0.1" or "localhost", some servers also need port info
 * DB_NAME: name of the database. please note: database and database table are not the same thing
 * DB_USER: user for your database. the user needs to have rights for SELECT, UPDATE, DELETE and INSERT.
 * DB_PASS: the password of the above user
 */
define("DB_HOST", "localhost");
define("DB_NAME", "imobi");
define("DB_USER", "root");
define("DB_PASS", "");