The wp_enqueue_scripts hook doesn’t work at all, not from plugin, not from the template, not for frontend, not for admin pages!

The wp_enqueue_scripts function is hooked to run on the wp_head action, which is triggered by the wp_head() function.

This function should be placed within the <head> tag of your theme’s markup.

If we refer to the core file default-filters.php, we can see the many functions that rely on wp_head for output.

error code: 523