Exception in thread "main"NoNodeAvailableException[None of the configured nodes are available

elasticsearch 연결이 성공했지만 다음 오류가 발생합니다. 노드를 사용할 수 없다는 뜻입니다.

Exception in thread "main" NoNodeAvailableException[None of the configured nodes are available: [{#transport#-1}{q-OhKPN_TjaYVSUpgbNQGQ}{127.0.0.1}{127.0.0.1:9300}]]
    at org.elasticsearch.client.transport.TransportClientNodesService.ensureNodesAreAvailable(TransportClientNodesService.java:347)
    at org.elasticsearch.client.transport.TransportClientNodesService.execute(TransportClientNodesService.java:245)
    at org.elasticsearch.client.transport.TransportProxyClient.execute(TransportProxyClient.java:60)
    at org.elasticsearch.client.transport.TransportClient.doExecute(TransportClient.java:371)
    at org.elasticsearch.client.support.AbstractClient.execute(AbstractClient.java:405)
    at org.elasticsearch.client.support.AbstractClient.execute(AbstractClient.java:394)
    at org.elasticsearch.client.support.AbstractClient$IndicesAdmin.execute(AbstractClient.java:1247)
    at org.elasticsearch.action.ActionRequestBuilder.execute(ActionRequestBuilder.java:46)
    at com.lin.TestClient.main(TestClient.java:47)

인터넷에서 언급된 흔한 문제, 예를 들어cluster를 제외하고.name,port가 일치하지 않습니다. (기본 접근 URL 포트는 9200이지만 연결 포트는 9300) 이외에 도입된transport 버전에 문제가 있는지 주의하십시오.
설치 디렉토리에 있는 로그 찾기 F:\elasticsearch-7.5.0-windows-x86_64\elasticsearch-7.5.0\log\my-application_server.json, 다음 질문을 출력했습니다.

2020-02-15T00:18:53,334+08:00", "level": "WARN", "component": "o.e.t.TcpTransport", "cluster.name": "my-application", "node.name": "DESKTOP-R3BLRIN", "message": "exception caught on transport layer [Netty4TcpChannel{localAddress=/127.0.0.1:9300, remoteAddress=/127.0.0.1:11931}], closing connection", "cluster.uuid": "HXtKTVCFSTiibfJBiea7tw", "node.id": "9juaKZHLQCWgm0G9oIe_kw" , 
"stacktrace": ["java.lang.IllegalStateException: Received message from unsupported version: [6.2.4] minimal compatible version is: [6.8.0]",

다음 버전을 수정하려면 프롬프트를 누르십시오.