Hello.
This issue, is relative of not loading JS and CSS files at that page.
The most probably your actual theme have some cache mechanism or your website is used the cache plugin for caching content.
Please try to deactivate one by one all your active plugins at the WordPress > Plugins menu. Then retest it again.
If its not help, please deactivate your active theme and active the default WordPress theme. And then retest it again. May be there exist some conflict with some active plugin or actual theme and just need to find the reason of that issue.
If the issue relative to your theme, please contact support of your theme about checking about the reason of this issue.
Usually such issue relative of not having
<?php wp_head(); ?>
in header.php file or because of using some cache system that load only previously cached data.
I can suggest that reason can be in this file:
<script type="text/javascript" src="https://testsite.villadaeva.eu/wp-content/themes/welcome_inn-parent/cache/min-js-310b095b59b07de720e153591344e34c.js?m=0"></script>
Can you check with support of your theme about purpose o this file, is this file contain only JS files of your theme or its also aggregate JS and CSS files of other plugins… ?
Kind Regards.