snapshots fails to send files to S3

When configuring snapshot to export backups to amazon the export always fails.

This is what happens when I configure an amazon destination:
Upon providing my Access Key ID and Secret Access Key, snapshot successfully connects to amazon. I can tell this because the field 'bucket name' list is automatically populated.

However, when I click on 'Test Connection' the output looks like this:

Connecting to AWS
Using SSL: Yes
Setting Region: US Standard (s3.amazonaws.com)
Using Storage: Standard
Using ACL: private
Sending file to: Bucket: sunilwilliams-general-backups: Directory: Error: Send file failed :403 :

It looks like the connection fails.

If I save the destination details anyway and provide them to a snapshot configuration, the snapshot will save but will not be exported to amazon.