Fatal error: Uncaught Error: Class "Aws\Api\Serializer\RestSerializer" not found in /srv/www/htdocs/moodle/lib/aws-sdk/src/Api/Serializer/RestXmlSerializer.php:10 Stack trace: #0 {main} thrown in /srv/www/htdocs/moodle/lib/aws-sdk/src/Api/Serializer/RestXmlSerializer.php on line 10