logstash - Email plugin connection refused -

i try use email plugin of logstash. instance of logstash crashes econnrefused error.

this content of config.conf file:

input {     generator {         lines => [ "logstash test: line 1" ]         count => 1     } } output {     email {          => "stuff@stuff.com"      }  } 

it fails following error:

errno::econnrefused: connection refused - connection refused initialize @ org/jruby/ext/socket/rubytcpsocket.java:126 open @ org/jruby/rubyio.java:1178 tcp_socket @ file:/opt/logstash/vendor/jar/jruby-complete-1.7.11.jar!/meta-inf/jruby.home/lib/ruby/1.9/net/smtp.rb:540 do_start @ file:/opt/logstash/vendor/jar/jruby-complete-1.7.11.jar!/meta -inf/jruby.home/lib/ruby/1.9/net/smtp.rb:549 timeout @ org/jruby/ext/timeout/timeout.java:126 do_start @ file:/opt/logstash/vendor/jar/jruby-complete-1.7.11.jar!/meta -inf/jruby.home/lib/ruby/1.9/net/smtp.rb:549 start @ file:/opt/logstash/vendor/jar/jruby-complete-1.7.11.jar!/meta -inf/jruby.home/lib/ruby/1.9/net/smtp.rb:519 deliver! @ /opt/logstash/vendor/bundle/jruby/1.9/gems/mail-2.5.3/lib/mai l/network/delivery_methods/smtp.rb:136 deliver! @ /opt/logstash/vendor/bundle/jruby/1.9/gems/mail-2.5.3/lib/mail/message.rb:245 receive @ /opt/logstash/lib/logstash/outputs/email.rb:251 handle @ /opt/logstash/lib/logstash/outputs/base.rb:86 initialize @ (eval):17 call @ org/jruby/rubyproc.java:271 output @ /opt/logstash/lib/logstash/pipeline.rb:266 outputworker @ /opt/logstash/lib/logstash/pipeline.rb:225 start_outputs @ /opt/logstash/lib/logstash/pipeline.rb:152