Fatal error: Uncaught Error: Class 'Symfony\Polyfill\Intl\Normalizer\Normalizer' not found in /opt/lampp/htdocs/io.core.websocket/vendor/symfony/polyfill-intl-normalizer/Resources/stubs/Normalizer.php:3 Stack trace: #0 {main} thrown in /opt/lampp/htdocs/io.core.websocket/vendor/symfony/polyfill-intl-normalizer/Resources/stubs/Normalizer.php on line 3