Fatal error: Uncaught Error: Class 'AC\Column' not found in C:\xampp\htdocs\wp-content\plugins\admin-columns-pro\admin-columns\classes\Column\Placeholder.php:8 Stack trace: #0 {main} thrown in C:\xampp\htdocs\wp-content\plugins\admin-columns-pro\admin-columns\classes\Column\Placeholder.php on line 8