Failed to open Bucket with transport-couchbase plugin , Elasticsearch with couchbase

I am using Couchbase 4.0 and when I try to make a XDCR replication over elastic search server then its constantly giving me
< timestamp> : Failed to get bucket user
I have followed all the steps that are given,
Please help me out.!!

What versions of elastic search and connector are you using? Be aware that things have changed quickly with Elastic, so the version matching needs to be a bit specific.

If you’re off the current supported versions, @WillGardella may be able to advise on how to help.