AWS -> S3 -> Fine Uploader, fails region in callback false

I wrote a server like this: Link

My upload script looks like (onpage script):

var uploader = new qq.s3.FineUploader({
        element: document.getElementById("fineUploader"),
        request: {
            endpoint: "bucket.s3-eu-central-1.amazonaws.com",
            accessKey: "accesskey",
        },
        signature: {
            version: 4,
            region: "eu-central-1",
            endpoint: "https:127.0.0.1:8000/s3handler"
        },
        retry: {
            enableAuto: false
        },
        chunking: {
            enabled: true
        },
        paste: {
            targetElement: document,
            promptForName: true
        }
    });

I get the credentials, after upload I get the error message:

the region 'us-east-1' is wrong; expecting 'eu-central-1'

At the Node Server is the x-amz-credential returns also at region us-east

vaildkey/vailduntil/us-east-1/s3/aws4_request

But I added already at the client (see first code) region to the signature. Also I added to the expectedHostname the same link as endpoint at the top, and start the server with aws.config.region='eu-central-1';

What did I make wrong that the region does not changes?

via ich