Comment 1 for bug 2047052

Is there any way to get the complete request and code 400 response from S3?

"An error occurred (400) when calling the HeadBucket operation: Bad Request" is really generic and could just be about wrong access key / credentials / region. Where do those credentials come from in this case? Are they set and valid?

Mind you boto3 has all the AWS magic, so ENV variables such as AWS_ACCESS_KEY_ID have the highest preference over e.g. an AWS_PROFILE - see https://docs.aws.amazon.com/cli/latest/topic/config-vars.html.