I now have the same error for each node
[WARN ] 2023-04-25 15:05:41.064 [Ruby-0-Thread-9: /usr/share/logstash/vendor/bundle/jruby/2.6.0/gems/logstash-output-elasticsearch-11.13.1-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:213] elasticsearch - Attempted to resurrect connection to dead ES instance, but got an error {:url=>"https://es01:9200/", :exception=>LogStash::Outputs::ElasticSearch::HttpClient::Pool::HostUnreachableError, :message=>"Elasticsearch Unreachable: [https://es01:9200/][Manticore::SocketException] Connect to es01:9200 [es01/172.21.0.4] failed: Connection refused"}
[WARN ] 2023-04-25 15:05:41.345 [Ruby-0-Thread-9: /usr/share/logstash/vendor/bundle/jruby/2.6.0/gems/logstash-output-elasticsearch-11.13.1-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:213] elasticsearch - Attempted to resurrect connection to dead ES instance, but got an error {:url=>"https://es02:9200/", :exception=>LogStash::Outputs::ElasticSearch::HttpClient::Pool::BadResponseCodeError, :message=>"Got response code '401' contacting Elasticsearch at URL 'https://es02:9200/'"}
[WARN ] 2023-04-25 15:05:41.507 [Ruby-0-Thread-9: /usr/share/logstash/vendor/bundle/jruby/2.6.0/gems/logstash-output-elasticsearch-11.13.1-java/lib/logstash/outputs/elasticsearch/http_client/pool.rb:213] elasticsearch - Attempted to resurrect connection to dead ES instance, but got an error {:url=>"https://es03:9200/", :exception=>LogStash::Outputs::ElasticSearch::HttpClient::Pool::BadResponseCodeError, :message=>"Got response code '401' contacting Elasticsearch at URL 'https://es03:9200/'"}
Do I need to configure some user/password somewhere ?