Fatal error: Uncaught Error: Call to undefined function add_action() in /home/globaltourtourds/public_html/wp-content/plugins/wp-travel/core/ajax/cart.php:18 Stack trace: #0 /home/globaltourtourds/public_html/wp-content/plugins/wp-travel/core/ajax/cart.php(166): WP_Travel_Ajax_Cart::init() #1 {main} thrown in /home/globaltourtourds/public_html/wp-content/plugins/wp-travel/core/ajax/cart.php on line 18