Fatal error: Uncaught Error: Class 'Nextend\Framework\Form\AbstractField' not found in C:\xampp\htdocs\wp-content\plugins\smart-slider-3\Nextend\Framework\Form\Element\Breakpoint.php:13 Stack trace: #0 {main} thrown in C:\xampp\htdocs\wp-content\plugins\smart-slider-3\Nextend\Framework\Form\Element\Breakpoint.php on line 13