Paypal IPN挂钩无法正常工作

I have created a plugin to send email to user after their donation using paypal. But problem is that user not receiving any email. Please kindly check my code below. I am also using plugin called "PayPal IPN for WordPress" to get information of donation.

<?php
/*
Plugin Name: PayPal IPN Send Email
Plugin URI: http://www.trustedwebsolution.com/
Description: Hook tester for PayPal IPN for WordPress plugin.
Author: Jhishu Singha
Version: 1.0.0
*/


add_action('paypal_ipn_for_wordpress_payment_status_processed', 'paypal_ipn_for_wordpress_payment_email', 10, 1);
function paypal_ipn_for_wordpress_payment_email($posted) {
    // Parse data from IPN $posted array

    $dir = plugin_dir_url( __FILE__ );
    $item_name = isset($posted['item_name']) ? $posted['item_name'] : '';
    $payment_gross = isset($posted['payment_gross']) ? $posted['payment_gross'] : '';
    $first_name = isset($posted['first_name']) ? $posted['first_name'] : '';
    $last_name = isset($posted['last_name']) ? $posted['last_name'] : '';
    $payer_email = isset($posted['payer_email']) ? $posted['payer_email'] : '';
    $subscr_date = isset($posted['subscr_date']) ? $posted['subscr_date'] : '';

    /**
     * At this point you can use the data to generate email notifications,
     * update your local database, hit 3rd party web services, or anything
     * else you might want to automate based on this type of IPN.
     */
    if($item_name == 'ATF Donation') { 
    $to = $payer_email;
    $subject = 'Email from Adaptive Training Foundation';
    $message = 'Thanks for donation';
    $headers = array('Content-Type: text/html; charset=UTF-8');
    wp_mail( $to, $subject, $message, $headers );
    } else {
        // No email
    }
}
?>

I am trying to solve it for few days. But no luck. Thanks in advance for help.

I think you should use a different hook. Instead of paypal_ipn_for_wordpress_payment_status_processed use paypal_ipn_for_wordpress_payment_status_completed and see if that helps.

Also, for testing purposes, I would add an email to yourself in the else section of your statement so that you'll get something if the code falls there and you won't think the IPN simply never ran.