Fatal error: Uncaught Error: Undefined constant "PHPEXCEL_ROOT" in /var/www/html/includes/PHPExcel/Autoloader.php:73 Stack trace: #0 /var/www/html/includes/PHPExcel/Autoloader.php(36): PHPExcel_Autoloader::Load() #1 {main} thrown in /var/www/html/includes/PHPExcel/Autoloader.php on line 73