logstash error

{:timestamp=>"2016-02-26T23:06:28.297000+0000",
:message=>"gelf listener died",
:exception=>#<LogStash::Json::ParserError: Invalid UTF-8 start byte 0x9b at [Source: [B@35db01d4; line: 1, column: 281]>,
:backtrace=>["/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.2.2-java/lib/logstash/json.rb:41:in `jruby_load'",
"/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.2.2-java/lib/logstash/json.rb:38:in `jruby_load'",
"/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-gelf-2.0.2/lib/logstash/inputs/gelf.rb:99:in `udp_listener'",
"/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-gelf-2.0.2/lib/logstash/inputs/gelf.rb:63:in `run'",
"/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.2.2-java/lib/logstash/pipeline.rb:331:in `inputworker'",
"/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.2.2-java/lib/logstash/pipeline.rb:325:in `start_input'"],
:level=>:warn}