Failure creation s3 repository

Elastic Stack Elasticsearch
1

Hi everyone,

I was trying to create and configure S3 repository and got an error creating it.
I have installed the elasticsearch-aws-plugin-2.7.1.

My query is:
curl -XPUT 'http://localhost:9200/_snapshot/s3-backup' -d '{"type": "s3", "settings": {"bucket": "","region": "us-west-2", "access_key": "", "secret_key": "**"}}'

The error recieved:
"error":"RepositoryException[[s3-backup] failed to create repository]; nested: NoClassSettingsException[failed to load class with value [s3]; tried [s3, org.elasticsearch.repositories.S3RepositoryModule, org.elasticsearch.repositories.s3.S3RepositoryModule, org.elasticsearch.repositories.s3.S3RepositoryModule]]; nested: ClassNotFoundException[org.elasticsearch.repositories.s3.S3RepositoryModule]; ","status":500}

Any help?
thanks.