The error shown as follows:

New Aws regions from 2016 are using the new AWS4-HMAC-SHA256 authorization mechanism. Other appliction like webmin use the help of the AWS-CLI installed on the server to make the right auth call. Please update the S3 files to support the new authorization mechanism for all new AWS regions from 2016.Below is the error from the logs after enabling the S3 cloud files.

[ow_core_log][Warning]Message:S3::putObject():[InvalidRequest] The authorization mechanism you have provided is not supported. Please use AWS4-HMAC-SHA256.