Not changing the default permalink structure

The default permalink structure for WordPress is NOT optimized for SEO. While you’ll want to optimize each post/page URL for SEO when creating the page, changing the default setting is needed to properly do that. The good news is that this is easy to do.

The fix:

To change the permalink structure in WordPress, go to Settings => Permalinks and choose “Post name”. If your site has existing content under another setting, you want to redirect old permalinks (URLs) to the new ones. There are free plugins that will help you do this, or you can search for how to do this with an .htaccess file and add the redirects in Yoast.