Fatal error: Uncaught Error: Class "Composer\Installer\MetapackageInstaller" not found in /home/marcgron/www/SSA/v2/vendor/symfony/flex/src/SymfonyPackInstaller.php:16 Stack trace: #0 {main} thrown in /home/marcgron/www/SSA/v2/vendor/symfony/flex/src/SymfonyPackInstaller.php on line 16