Uploading objects to S3 Bucket

We have sync'ed a couple of objects (around 55Gigs) onto s3 from aws command line. We need to sync these to an EC2 instance, but the download fails.

On investigating we found that the objects that were synced to S3 do not have an owner name, and no permissions. And when we try to add permissions, it fails and says permission denied.

We have tried adding metadata from S3 properties, and also tried --grants from aws cli. Neither of them have worked.

Is there any suggestion on how to assign an owner to all objects within the folders and subsequently provide permissions?

Thanks.