I found a solution i dont know why it works now, but it works i guess Adding this to my RestClient

.requestInterceptor(new ClientHttpRequestInterceptor() {
    @Override
    public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException {
        log.info(request.toString());
        return execution.execute(request, body);
    }
})

Somehow works also it removed the Transfer-Encoding header