Elasticx to query ES

i am using elasticx to query my ES for getting some logs from there, so i did this configurations:

*) mix.exs:
{:elastix, "~> 0.9.0"}, {:httpoison, "~> 1.4"}, {:poison, "~> 3.0"}, {:retry, "~> 0.8"}

*) myFile.ex:

res0 = Elastix.Index.create("http://15.237.40.183:9200", "twitter", %{})

    Logger.debug("\n\n---------- res0 = #{inspect(res0)} ")

==> i am getting this error:

[debug] 

---------- res0 = {:error, %HTTPoison.Error{id: nil, reason: :closed}}

can any one give me some ideas about what happen here please ? and where i should normaly specify my username and password for ES ?