Fatal error: Uncaught Error: Class "yii\base\Widget" not found in /var/www/html/prod/vendor/mtangoo/yii2-fullcalendar/src/Calendar.php:20 Stack trace: #0 {main} thrown in /var/www/html/prod/vendor/mtangoo/yii2-fullcalendar/src/Calendar.php on line 20