Creating custom archive page

I want to make a custom archive page for a custom post type called ‘portfolio’ (https://prnt.sc/qd2r0o). Therefore, I made the template files called ‘archive-portfolio.php’ and ‘portflio_cat.php’, but none of these files seem to be working. I always see the default archive.php page. What am I doing wrong here?

• This topic was modified 5 years, 3 months ago by Jan Dembowski. Reason: Moved to Fixing WordPress, this is not a Developing with WordPress topic

The page I need help with: [log in to see the link]