Fatal error: Uncaught Error: Class "Composer\Installers\BaseInstaller" not found in /srv/www/cntait.org/www/site.tree/public/wp-content/plugins/wp-nested-pages/vendor/composer/installers/src/Composer/Installers/SilverStripeInstaller.php:6 Stack trace: #0 {main} thrown in /srv/www/cntait.org/www/site.tree/public/wp-content/plugins/wp-nested-pages/vendor/composer/installers/src/Composer/Installers/SilverStripeInstaller.php on line 6