Debugging wp_mail() can be a lot easier with this simple method.
It will display a more helpful error message (the original phpmailer error) than Wordpress will by default.
Just add this function to display the real wp_mail() error.
But only use this for debugging.

// show wp_mail() errors
add_action( 'wp_mail_failed', 'onMailError', 10, 1 );
function onMailError( $wp_error ) {
	echo "<pre>";
    print_r($wp_error);
    echo "</pre>";
}