SMTP Gmail Codeigniter 3

I have a problem with smtp gmail using codeigniter 3, I created this code in the controller folder with the file name Auth.php. so when the user clicks the register button a verification email will be sent to the email that was registered by the user

`   private function _sendEmail()
    { 
        $config = [
            'protocol' => 'smtp',
            'smtp_host' => 'ssl://smtp.googlemail.com',
            'smtp_users' => '***',
            'smtp_pass' => '***',
            'smtp_port' =>  465,
            'mailtype' => 'html',
            'charset' => 'utf-8',

        ];

        $this->email->set_newline("\r\n");
        $this->load->library('email',$config); 
        $this->email->initialize($config);

        $this->email->from('Email Sender', 'Full name in email');
        $this->email->to('Recieved email');
        $this->email->subject('Testing');
        $this->email->message('coba coba');

        if($this->email->send()) {
            return true;
        } else {
            echo $this->email->print_debugger();
            die;
        }
    }`