Rebuild WordPress Permalinks To Fix 404 Pages
After you install Zeno theme, you should resave the WordPress permalinks. Otherwise, you might receive a 404 error when accessing product’s detail page.
To rebuild the permalinks structure you need to go to Settings->Permalinks.
Change your permalinks structure to “Post name”. This is the recommended option both for Zeno theme and from SEO perspective. Click on “Save Changes” even if you haven’t made any changes.
This action will rebuild the WordPress permalinks structure and should fix the 404 error.