AWS printed this

An error occurred (AccessDenied) when calling the PutObject operation: Access Denied

What it meansS3 rejected the upload because the credentials in use lack permission to write the object, or some policy explicitly denies it.

The first thing to checkCheck that the IAM policy allows s3:PutObject on the bucket ARN with /*, then check the bucket policy, KMS key access, and which credentials are active.

The walrus saysIt is always the IAM policy.