在消息发送上使用codeiniter电子邮件库我看到错误消息：未定义属性：CI_Email :: $ print_debugger

I am working on the Codeigniter email library on message send its displaying me an error message: Undefined property: CI_Email::$print_debugger. I have also checked this on my online server but not worked for me.

Here is code:

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class Welcome extends CI_Controller {

 function __construct()
{
    parent::__construct();
}
public function index()
{
    $data['main_content'] = 'home';
    $this->load->view("template", $data);
}
public function refinanceEmail()
{

    $zip                    = $this->input->post("zip");
    $propertyValue          = $this->input->post("propertyValue");
    $mortgageBalance        = $this->input->post("mortgageBalance");
    $creditscore            = $this->input->post("creditscore");
    $city                   = $this->input->post("city");
    $state                  = $this->input->post("state");
    $firstName              = $this->input->post("firstName");
    $lastName               = $this->input->post("lastName");
    $phone                  = $this->input->post("phone");

    // Message
    $message  = "This message is related to Refinance." . "
" . "
";
    $message .= "Zip:: " . $zip . "
";
    $message .= "Property Value:: " . $propertyValue . "
";
    $message .= "Mortgage Balance:: " . $mortgageBalance . "
";
    $message .= "Credit Score:: " . $creditscore . "
";
    $message .= "City:: " . $city . "
";
    $message .= "State:: " . $state . "
";
    $message .= "First Name:: " . $firstName. "
";
    $message .= "Last Name:: " . $lastName . "
";  
    $message .= "Phone:: " . $phone . "
";     


    $config = Array(
        'protocol' => '',
        'smtp_host' => 'mail.********.net',
        'smtp_port' => 25,
        'smtp_user' => '*****@******.net',
        'smtp_pass' => '********',
        'mailtype'  => 'text', 
        'charset'   => 'utf-8'
    );         
    $this->load->library('email', $config);

    $this->email->set_newline("
");

    $this->email->from($phone, $firstName . " " . $lastName);
    $this->email->to("submit@example.net");
    $this->email->subject('My Subject');
    $this->email->message($message);

    if($this->email->send())
    {
        redirect('/welcome/thankyou');
    }
    else
    {
        show_error($this->email->print_debugger);
        return false;
    }
}
public function thankyou()
{
    $data['main_content'] = 'thankyou';
    $this->load->view("template", $data);
}
}

print_debugger is a function, not a property so

show_error($this->email->print_debugger);

should be

show_error($this->email->print_debugger());

From this output you'll hopefully be able to work out why the call to send() returned false