Cloud can not send logs to elasticsearch

[Xu_Zhao]

I have a elasticesearch server installed.
when I access curl 'http://192.168.3.1:9200/?pretty'
{
"name" : "Tom Foster",
"cluster_name" : "elasticsearch",
"version" : {
"number" : "2.1.0",
"build_hash" : "72cd1f1a3eee09505e036106146dc1949dc5dc87",
"build_timestamp" : "2015-11-18T22:40:03Z",
"build_snapshot" : false,
"lucene_version" : "5.3.1"
},
"tagline" : "You Know, for Search"
}

then I want to deploy some apps to cloud, and bind the service which can send out logs
to elastic search.

1. create a user-provided service logaas,
2. set "Syslog Drain Url" to elastic search Url as "syslog://192.168.3.1:9200"(here I am not if I should use the elasticsearch url)
3. bind my app to service logaas

but I got the error message : Syslog Drain: Error when writing,Backing off for 1ms