I think you have a problem with custom portfolio slug.
This can happen if you have replaced the default Portfolio Page Slug.
If this is the case, try to return default portfolio page slug (agama_portfolio) to the “Portfolio Page Slug” field in the Customizing-> Portfolio menu. https://prnt.sc/i4axvs
If this doesn’t help, please give me the Admin login User / Pass in private reply so I can check the Issue directly on your website.