Warning: Connection refused on port 9304

Elastic Stack Elasticsearch
1

I am running ES on a local computer. I am encountering this error:

[2025-06-30T15:06:05,304][WARN ][o.e.d.PeerFinder         ] [localhost.localdomain] address [[::1]:9304], node [unknown] discovery result: [][[::1]:9304] connect_exception: Failed execution: io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection refused: /[0:0:0:0:0:0:0:1]:9304: Connection refused: /[0:0:0:0:0:0:0:1]:9304: Connection refused; for summary, see logs from org.elasticsearch.cluster.coordination.ClusterFormationFailureHelper; for troubleshooting guidance, see https://www.elastic.co/docs/troubleshoot/elasticsearch/discovery-troubleshooting?version=9.0

As mentioned on Required port, port 9300 and onward are for intra-cluster communication. But I am running a single node cluster.

Can someone explain the meaning of this warning ?

Additional info:

  1. No firewall running, no program blocking the port
  2. ES service is running under the elasticsearch user and group
  3. Content of elasticsearch.yml:
path.data: /var/lib/elasticsearch
path.logs: /var/log/elasticsearch
network.host: 192.168.3.1
http.port: 9200


xpack.security.enabled: true

xpack.security.enrollment.enabled: false

xpack.security.http.ssl:
  enabled: false
  keystore.path: certs/http.p12

xpack.security.transport.ssl:
  enabled: true
  verification_mode: certificate
  keystore.path: certs/transport.p12
  truststore.path: certs/transport.p12
cluster.initial_master_nodes: ["localhost"]

http.host: 0.0.0.0