When you install a new theme or plugin in your WordPress site, it can sometimes happen that specific pages display a 404 error page. This is due to the addition of new custom post types.
Indeed, custom post types use a specific URL structure which is not defined by default in your site. Happily, fixing this issue only requires 2 clics!
- In your WordPress dashboard, go to Settings > Permalink
- Hit the Save button without modifying any setting
This simple operation will update the permalinks structure and should fix the 404 error pages you were seeing.