core/templates/untrustedDomain.php
<?php /** @var $_ array */ ?>
<ul class="error-wide">
<li class='error'>
<?php p($l->t('You are accessing the server through an untrusted domain.')); ?><br>
<p class='hint'>
<?php p($l->t('Please contact your administrator. If you are an administrator of this instance, configure the "trusted_domains" setting in config/config.php. ')) ?>
<?php print_unescaped($l->t('An example configuration is provided in config/config.sample.php or at the <a target="_blank" rel="noreferrer" href="%s">documentation</a>.', [link_to_docs(\OCP\Constants::DOCS_ADMIN_UNTRUSTED_DOMAIN)])); ?>
</p>
</li>
</ul>