By enabling the trace, I now see the following as the root cause.

**"error": "Content-Type header [application/x-ldjson] is not supported",**
**  "status": 406**

This happens in bulk indexing while index.js parsing the items from data.json file and trying to index as a bulk.

I see a change log from elasticsearch says following

_13.0.0 (Apr 24 2017)_
_bulk and other APIs that send line-delimited JSON bodies now use the Content-Type: application/x-ndjson header #507_

Any idea how to resolve this content type issue in index.js?