Logstash error after filebeat restarted

I got error in Logstash every time I restart Filebeat. To make logstash work again, I have to kll the Logstash process and restart it. How to fix it?

Here is the error

{:timestamp=>"2016-06-15T00:48:30.697000-0400", :message=>"Attempted to send a bulk request to Elasticsearch configured at '["http://127.0.0.1:9200/"]', but an error occurred and it failed! Are you sure you can reach elasticsearch from this machine using the configuration provided?", :error_message=>"[403] {"error":{"root_cause":[{"type":"security_exception","reason":"action [indices:data/write/bulk] is unauthorized for user [user_agent]"}],"type":"security_exception","reason":"action [indices:data/write/bulk] is unauthorized for user [user_agent]"},"status":403}", :error_class=>"Elasticsearch::Transport::Transport::Errors::Forbidden", :backtrace=>["/opt/logstash/vendor/bundle/jruby/1.9/gems/elasticsearch-transport-1.0.17/lib/elasticsearch/transport/transport/base.rb:201:in __raise_transport_error'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/elasticsearch-transport-1.0.17/lib/elasticsearch/transport/transport/base.rb:312:inperform_request'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/elasticsearch-transport-1.0.17/lib/elasticsearch/transport/transport/http/manticore.rb:67:in perform_request'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/elasticsearch-transport-1.0.17/lib/elasticsearch/transport/client.rb:128:inperform_request'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/elasticsearch-api-1.0.17/lib/elasticsearch/api/actions/bulk.rb:88:in bulk'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-2.6.2-java/lib/logstash/outputs/elasticsearch/http_client.rb:53:innon_threadsafe_bulk'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-2.6.2-java/lib/logstash/outputs/elasticsearch/http_client.rb:38:in bulk'", "org/jruby/ext/thread/Mutex.java:149:insynchronize'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-2.6.2-java/lib/logstash/outputs/elasticsearch/http_client.rb:38:in bulk'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-2.6.2-java/lib/logstash/outputs/elasticsearch/common.rb:164:insafe_bulk'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-2.6.2-java/lib/logstash/outputs/elasticsearch/common.rb:101:in submit'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-2.6.2-java/lib/logstash/outputs/elasticsearch/common.rb:86:inretrying_submit'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-2.6.2-java/lib/logstash/outputs/elasticsearch/common.rb:29:in multi_receive'", "org/jruby/RubyArray.java:1653:ineach_slice'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-output-elasticsearch-2.6.2-java/lib/logstash/outputs/elasticsearch/common.rb:28:in multi_receive'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.2-java/lib/logstash/output_delegator.rb:130:inworker_multi_receive'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.2-java/lib/logstash/output_delegator.rb:129:in worker_multi_receive'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.2-java/lib/logstash/output_delegator.rb:114:inmulti_receive'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.2-java/lib/logstash/pipeline.rb:301:in output_batch'", "org/jruby/RubyHash.java:1342:ineach'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.2-java/lib/logstash/pipeline.rb:301:in output_batch'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.2-java/lib/logstash/pipeline.rb:232:inworker_loop'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-2.3.2-java/lib/logstash/pipeline.rb:201:in start_workers'"], :client_config=>{:hosts=>["http://127.0.0.1:9200/"], :ssl=>nil, :transport_options=>{:socket_timeout=>0, :request_timeout=>0, :proxy=>nil, :ssl=>{}}, :transport_class=>Elasticsearch::Transport::Transport::HTTP::Manticore, :headers=>{"Authorization"=>"Basic Y2VybWF0aV9hZ2VudDpDZXJtYXRIZWJhdA=="}, :logger=>nil, :tracer=>nil, :reload_connections=>false, :retry_on_failure=>false, :reload_on_failure=>false, :randomize_hosts=>false, :http=>{:scheme=>"http", :user=>nil, :password=>nil, :port=>9200}}, :level=>:error}

That's a 403 error, ie an authorisation one.
Are you using shield?

Yes I'm using shield