Server/pages/404.php

<?php
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
?>
<div class="row justify-content-center">
    <div class="col-12 col-sm-10 col-md-8 col-lg-6">
        <div class="alert alert-warning"><b><?php $Strings->get("404 error");?></b><br /> <?php $Strings->get("page not found"); ?></div>
    </div>
</div>