Envio de email usando wp, prueba.

envio_mail.php

<?php
$uploaddir = trim(ABSPATH, '/') . DIRECTORY_SEPARATOR . 'uploads' . DIRECTORY_SEPARATOR;
$attachments = [];
foreach ($_FILES as $i => $data) {
	$uploadfile = $uploaddir . basename($data['name']);

	if (move_uploaded_file($data['tmp_name'], $uploadfile)) {
		$attachments[$i] = $uploadfile;
	}
}

wp_mail($conReceptor,$conAsunto,$conMensaje, $attachments, array( 'Reply-To: '.$conNombre.' <'.$conCorreo2.'>'));