I use aws-java-sdk-bom in order to upload file:

final PutObjectRequest putRequest = new PutObjectRequest(bucketName, blobKey.toString(), input, metadata);
putRequest.setCannedAcl(CannedAccessControlList.PublicRead);

final ProgressTracker progress = new ProgressTracker();
transferManager.upload(putRequest, new S3ProgressListenerChain(progress));

and I noticed that sometimes if I try to access the URL right after the request is successfully done (mostly for big >20Mb files) it responses with 403.. After a second - everything is OK. Is there any timeout or something?