Fatal error: Uncaught Error: Class "PHPExcel_Writer_Abstract" not found in C:\xampp\htdocs\crop_db\libs\phpoffice\PHPExcel\Writer\Excel5.php:36 Stack trace: #0 {main} thrown in C:\xampp\htdocs\crop_db\libs\phpoffice\PHPExcel\Writer\Excel5.php on line 36