Notice: Use of undefined constant PHPEXCEL_ROOT - assumed 'PHPEXCEL_ROOT' in /opt/lampp/htdocs/squidv2-stage-api/vendor/phpoffice/phpexcel/Classes/PHPExcel/Autoloader.php on line 73

Fatal error: Uncaught Error: Class 'PHPExcel_Shared_String' not found in /opt/lampp/htdocs/squidv2-stage-api/vendor/phpoffice/phpexcel/Classes/PHPExcel/Autoloader.php:36 Stack trace: #0 {main} thrown in /opt/lampp/htdocs/squidv2-stage-api/vendor/phpoffice/phpexcel/Classes/PHPExcel/Autoloader.php on line 36