Hello, @Dennis,
Please go to WP-Dashboard >> Settings >> Permalinks and from there set your permalinks setting as shown in this screenshot: https://postimg.cc/pyDP7Cpv
Then please go to WooCommerce >> Settings >> Products >> General and set your Shop page from there: https://postimg.cc/N9tQf2zS
And finally check back to your site after removing the cache and if still the issue will persist then please share your site WP Admin URL and Credentials with me in the private content area of this topic so that I’ll check it for you on your site and assist you accordingly.
Regards 8Themes Team.