Gelf listener died


I have a lot of errors like this (every 5 seconds) :

  :message=>"gelf listener died",
  :exception=>#<SocketError: bind: name or service not known>,
    "org/jruby/ext/socket/ `bind'",
    "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-gelf-2.0.7/lib/logstash/inputs/gelf.rb:98:in `udp_listener'",
    "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-gelf-2.0.7/lib/logstash/inputs/gelf.rb:77:in `run'",
    "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.4.0-java/lib/logstash/pipeline.rb:342:in `inputworker'",
    "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.4.0-java/lib/logstash/pipeline.rb:336:in `start_input'"

here is my input config :

 input {
  beats {
    port => 5044
  gelf {
    port => 12201
    # use_tcp => true
    type => "gelf"

If I knew which "name or service" it's trying to connect to, it would help.
For the moment, I have no clue :confused:

Thanks for any help.

I've monkey-patched the code and the exception is raised when trying to bind to