Fatal error: Uncaught Error: Class 'Aws\Api\Serializer\RestSerializer' not found in /data/newpmo/web/plugin/aws_s3/Aws/Api/Serializer/RestJsonSerializer.php:11 Stack trace: #0 {main} thrown in /data/newpmo/web/plugin/aws_s3/Aws/Api/Serializer/RestJsonSerializer.php on line 11