Fatal error: Uncaught Exception: Composer autoloader could not be found. Install dependencies with `composer install` and try again. in /home/www/confitures2/vendor/phpoffice/phpspreadsheet/src/Bootstrap.php:22 Stack trace: #0 /home/www/confitures2/vendor/phpoffice/phpspreadsheet/samples/Header.php(9): require_once() #1 /home/www/confitures2/vendor/phpoffice/phpspreadsheet/samples/index.php(3): require_once('/home/www/confi...') #2 {main} thrown in /home/www/confitures2/vendor/phpoffice/phpspreadsheet/src/Bootstrap.php on line 22