Fatal error: Uncaught Error: Class 'Composer\Installer\LibraryInstaller' not found in /var/www/html/wp-content/plugins/kirki/kirki-composer/composer/installers/src/Composer/Installers/Installer.php:15 Stack trace: #0 {main} thrown in /var/www/html/wp-content/plugins/kirki/kirki-composer/composer/installers/src/Composer/Installers/Installer.php on line 15