PHP Fatal error: Call to undefined function WP_Filesystem() [closed]

Question

"internal server error"

wp-content/themes/xxxxxx/inc/custom-functions.php on line 529

Answer 1

The error is in custom-functions.php line 529 where you might be using file system function outside of admin, you can fix this by including the core admin file.php file like this.

require_once(ABSPATH . 'wp-admin/includes/file.php');