Logstash fails to send events to ES when one instance of cluster stops

Elastic Stack Logstash
1

Hi,

I have this config. Logstash (2.3*) and ES (2.1.1).

Logstash ES output are configured with two ES servers in cluster: hosts => ["192.168.48.120","192.168.48.121"]

There are 2 ES instances in this IPs configured in a cluster. When I stop one of the servers, Logstash stops to index events while one of the nodes are down.
Error that I'm getting from ES:
message=>"Attempted to send a bulk request to Elasticsearch configured at '["http://192.168.48.120:9200", "http://192.168.48.121:9200"]', but an error occurred and it failed! Are you sure you can reach elasticsearch from this machine using the configuration provided?", :error_message=>"192.168.48.120:9200 failed to respond", :error_class=>"Manticore::ClientProtocolException"

Logstash stops to send events to ES. Why I'm getting this error if the other instance of ES is up and running?

Thanks!