Fatal error: Uncaught Error: Undefined constant "WC_VERSION" in /usr/www/renaz/modbodfit/wp-content/plugins/woocommerce-appointments/includes/class-wc-appointments-rest-api.php:20 Stack trace: #0 /usr/www/renaz/modbodfit/wp-content/plugins/woocommerce-appointments/includes/class-wc-appointments-rest-api.php(67): WC_Appointments_REST_API->__construct() #1 {main} thrown in /usr/www/renaz/modbodfit/wp-content/plugins/woocommerce-appointments/includes/class-wc-appointments-rest-api.php on line 20