CSS not showing up in my website Only HTML Displaying

Check you are addressing the CSS file correctly. How is it being called?

The url should be along the lines of ht|tp://yoursite.com/wordpress/wp-content/themes/yourtheme/style.css you’ll find somewhere that it’s loading as ht|tp://localhost/and so it will load correctly on your machine but not on anyone else’s.

Have a look in Developer Tools for the URL of style.css

error code: 523