This looks like an issue with the configuration of the Amazon S3 Filesystem options, or an error in your S3 IAM Permissions.

I have updated the Amazon S3 Filesystem plugin on your site, and corrected some values in the S3 Filesystem configuration, such as the bucket name and remove the invalid CName value.

You still need to select the Endpoint where the bucket is located, otherwise the S3 Filesystem will not work.

You can use the $username variable in the File Directory Path to assign a folder to each user, eg: images/$username

and all users must storge on one folder as well.

Unfortunately this is currently not possible.

You can restrict users to a specific folder using the $username variable, or a a group of users, eg: Author using the $usergroup variable, eg:images/$usergroup

You can add further restrictions using a Directory Filter, removing access to a specific folder in the File Directory Path.