Dear Team,
we received below error when we are executing logstash. "we have a trail license till 9th of jan 2018"
[ERROR][logstash.licensechecker.licensemanager] Unable to retrieve license information from license server {:message=>"Elasticsearch Unreachable: [http://localhost:9200/][Manticore::SocketException] Connection refused (Connection refused)", :class=>"LogStash::Outputs::ElasticSearch::HttpClient::Pool::HostUnreachableError"}
[2017-12-27T08:21:55,985][WARN ][logstash.licensechecker.xpackinfo] Nil response from License Server
[2017-12-27T08:21:56,044][INFO ][logstash.pipeline ] Pipeline started {"pipeline.id"=>".monitoring-logstash"}
[2017-12-27T08:21:57,183][INFO ][logstash.outputs.elasticsearch] Elasticsearch pool URLs updated {:changes=>{:removed=>[], :added=>[http://logstash_system:xxxxxx@dcvels01.warbabank.com:9200/]}}
[2017-12-27T08:21:57,185][INFO ][logstash.outputs.elasticsearch] Running health check to see if an Elasticsearch connection is working {:healthcheck_url=>http://logstash_system:xxxxxx@dcvels01.warbabank.com:9200/, :path=>"/"}
[2017-12-27T08:21:57,396][WARN ][logstash.outputs.elasticsearch] Attempted to resurrect connection to dead ES instance, but got an error. {:url=>"http://logstash_system:xxxxxx@dcvels01.warbabank.com:9200/", :error_type=>LogStash::Outputs::ElasticSearch::HttpClient::Pool::BadResponseCodeError, :error=>"Got response code '503' contacting Elasticsearch at URL 'http://dcvels01.warbabank.com:9200/'"}
[2017-12-27T08:21:57,397][INFO ][logstash.outputs.elasticsearch] Using mapping template from {:path=>nil}
[2017-12-27T08:21:57,398][ERROR][logstash.outputs.elasticsearch] Failed to install template. {:message=>"Template file '' could not be found!", :class=>"ArgumentError", :backtrace=>["/home/logstash/logstash-6.0.0/vendor/bundle/jruby/2.3.0/gems/logstash-output-elasticsearch-9.0.0-java/lib/logstash/outputs/elasticsearch/template_manager.rb:37:in read_template_file'", "/home/logstash/logstash-6.0.0/vendor/bundle/jruby/2.3.0/gems/logstash-output-elasticsearch-9.0.0-java/lib/logstash/outputs/elasticsearch/template_manager.rb:23:inget_template'", "/home/logstash/logstash-6.0.0/vendor/bundle/jruby/2.3.0/gems/logstash-output-elasticsearch-9.0.0-java/lib/logstash/outputs/elasticsearch/template_manager.rb:7:in install_template'", "/home/logstash/logstash-6.0.0/vendor/bundle/jruby/2.3.0/gems/logstash-output-elasticsearch-9.0.0-java/lib/logstash/outputs/elasticsearch/common.rb:52:ininstall_template'", "/home/logstash/logstash-6.0.0/vendor/bundle/jruby/2.3.0/gems/logstash-output-elasticsearch-9.0.0-java/lib/logstash/outputs/elasticsearch/common.rb:25:in register'", "/home/logstash/logstash-6.0.0/logstash-core/lib/logstash/output_delegator_strategies/shared.rb:9:inregister'", "/home/logstash/logstash-6.0.0/logstash-core/lib/logstash/output_delegator.rb:43:in register'", "/home/logstash/logstash-6.0.0/logstash-core/lib/logstash/pipeline.rb:388:inregister_plugin'", "/home/logstash/logstash-6.0.0/logstash-core/lib/logstash/pipeline.rb:399:in block in register_plugins'", "org/jruby/RubyArray.java:1734:ineach'", "/home/logstash/logstash-6.0.0/logstash-core/lib/logstash/pipeline.rb:399:in register_plugins'", "/home/logstash/logstash-6.0.0/logstash-core/lib/logstash/pipeline.rb:800:inmaybe_setup_out_plugins'", "/home/logstash/logstash-6.0.0/logstash-core/lib/logstash/pipeline.rb:409:in start_workers'", "/home/logstash/logstash-6.0.0/logstash-core/lib/logstash/pipeline.rb:333:inrun'", "/home/logstash/logstash-6.0.0/logstash-core/lib/logstash/pipeline.rb:293:in `block in start'"]}
Kindly suggest me on this and guide me to fix this issue.