<?php
/**
 * Display errors
 */
if ( ! function_exists('debug_wpmail')) :

	function debug_wpmail( $result = false ) {

		if ( ! $result ) {

			global $ts_mail_errors;
			global $phpmailer;

			if ( ! isset($ts_mail_errors) )
				$ts_mail_errors = array();

			if ( isset($phpmailer) ) {
				$ts_mail_errors[] = $phpmailer->ErrorInfo;
			}

			print_r('<pre>');
			print_r($ts_mail_errors);
			print_r('</pre>');
		}
	}
endif;


/**
 * Usage
 */
$res = wp_mail($to, $subject, $message);
debug_wpmail($res); // Will print_r array of errors