How to configure IAM policy for S3 bucket?

Question

Amazon Web Services

When trying to upload a file to an S3 bucket via boto3, an error occurs:

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

in IAM, the AmazonS3FullAccess policy is attached to the user:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "s3:*",
            "Resource": "*"
        }
    ]
}

What could be the problem?

Answer 1

The fact is that it is not clear who is calling PutObject and whether these rights have been granted to this resource)

Answer 2

Perhaps the S3 bucket policy or ACL prohibits writing.
I advise you to create a new bucket and try to put files there. If it works out - repair it in your bucket, if not - I was wrong.