404: /wp-content/cache/autoptimize/css/child-theme.min.css.map

that is a request for a source map, as specified at the bottom of wp-content/themes/_pp/css/child-theme.min.css with

/*# sourceMappingURL=child-theme.min.css.map */

which resolves to wp-content/themes/_pp/css/child-theme.min.css.map.

Source maps are a tool for developers to see the origin of JS/ CSS files and are only requested if the browser console is open. As such they no impact on user experience because they are not requested by normal visitors (see this webpagetest.org waterfall chart for your site).

hope this clarifies,
frank

you’re welcome Michael, feel free to leave a review of the plugin and support here! 🙂