Fatal error: Uncaught Error: Class 'GuzzleHttp\Command\Guzzle\Serializer' not found in /opt/lampp/htdocs/vendor/qcloud/cos-sdk-v5/src/Serializer.php:13 Stack trace: #0 {main} thrown in /opt/lampp/htdocs/vendor/qcloud/cos-sdk-v5/src/Serializer.php on line 13