Fatal error: Uncaught Error: Interface 'Nextend\Framework\Form\ContainerInterface' not found in /home/legarden/www/app/plugins/nextend-smart-slider3-pro/Nextend/Framework/Form/ContainerContainedInterface.php:7 Stack trace: #0 {main} thrown in /home/legarden/www/app/plugins/nextend-smart-slider3-pro/Nextend/Framework/Form/ContainerContainedInterface.php on line 7