Fontawesome 5 icon free not showing

Simple tips to make sure your Fontawesome 5 free icons work:

Make sure you’re referencing the correct font family and weight in your css:

.icon::before {
	font-family: 'Font Awesome 5 Free';
	font-weight:900;
}

Check the enqueued CSS version is valid for the icon you want to use:

function load_font_awesome() {
    wp_enqueue_style( 'font-awesome-free', '//use.fontawesome.com/releases/v5.8.1/css/all.css' );
}
add_action( 'wp_enqueue_scripts', 'load_font_awesome' );