Fatal error: Uncaught Error: Call to undefined function add_action() in C:\xampp\htdocs\WAIT FOR DELETE\wp-content\plugins\jetpack\modules\custom-css\migrate-to-core.php:18 Stack trace: #0 C:\xampp\htdocs\WAIT FOR DELETE\wp-content\plugins\jetpack\modules\custom-css\migrate-to-core.php(257): Jetpack_Custom_CSS_Data_Migration::add_hooks() #1 {main} thrown in C:\xampp\htdocs\WAIT FOR DELETE\wp-content\plugins\jetpack\modules\custom-css\migrate-to-core.php on line 18