Fatal error: Uncaught Error: Undefined constant "CP_APPBOOK_DEFAULT_fp_from_email" in /home/customer/www/reserveren.atarobv.nl/public_html/wp-content/plugins/appointment-hour-booking/addons/reminder.addon.php:283 Stack trace: #0 /home/customer/www/reserveren.atarobv.nl/public_html/wp-includes/class-wp-hook.php(307): CPAPPB_Reminder->pp_Reminder_update_status('') #1 /home/customer/www/reserveren.atarobv.nl/public_html/wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters(NULL, Array) #2 /home/customer/www/reserveren.atarobv.nl/public_html/wp-includes/plugin.php(474): WP_Hook->do_action(Array) #3 /home/customer/www/reserveren.atarobv.nl/public_html/wp-settings.php(587): do_action('init') #4 /home/customer/www/reserveren.atarobv.nl/public_html/wp-config.php(78): require_once('/home/customer/...') #5 /home/customer/www/reserveren.atarobv.nl/public_html/wp-load.php(50): require_once('/home/customer/...') #6 /home/customer/www/reserveren.atarobv.nl/public_html/wp-blog-header.php(13): require_once('/home/customer/...') #7 /home/customer/www/reserveren.atarobv.nl/public_html/index.php(17): require('/home/customer/...') #8 {main} thrown in /home/customer/www/reserveren.atarobv.nl/public_html/wp-content/plugins/appointment-hour-booking/addons/reminder.addon.php on line 283