Apache nifi. Can't connect to Elastisearch due to a connection refused error

Hi there!

I'm facing a connection refused problem in my apache nifi instance trying to reach an Elasticsearch instance using a queryElasticsearchHttp processor.

The elasticsearch instance is reachable using CURL or in a web browser:

But when I try to execute the processor, it fails due to a connection refused error

Here is the configuration I have in the processor:

The server is not secured, but anyway I also tried to access with a valid user/password, facing the same error.

Here my log:

2023-11-24 09:03:14 2023-11-24 08:03:14,682 ERROR [Timer-Driven Process Thread-4] o.a.n.p.e.QueryElasticsearchHttp QueryElasticsearchHttp[id=018b15d7-f6fe-11ed-b48b-3fd75e47c7d4] Failed to read from Elasticsearch due to Failed to connect to localhost/127.0.0.1:9200, this may indicate an error in configuration (hosts, username/password, etc.). Routing to retry
2023-11-24 09:03:14 java.net.ConnectException: Failed to connect to localhost/127.0.0.1:9200
2023-11-24 09:03:14     at okhttp3.internal.connection.RealConnection.connectSocket(RealConnection.kt:297)
2023-11-24 09:03:14     at okhttp3.internal.connection.RealConnection.connect(RealConnection.kt:207)
2023-11-24 09:03:14     at okhttp3.internal.connection.ExchangeFinder.findConnection(ExchangeFinder.kt:226)
2023-11-24 09:03:14     at okhttp3.internal.connection.ExchangeFinder.findHealthyConnection(ExchangeFinder.kt:106)
2023-11-24 09:03:14     at okhttp3.internal.connection.ExchangeFinder.find(ExchangeFinder.kt:74)
2023-11-24 09:03:14     at okhttp3.internal.connection.RealCall.initExchange$okhttp(RealCall.kt:255)
2023-11-24 09:03:14     at okhttp3.internal.connection.ConnectInterceptor.intercept(ConnectInterceptor.kt:32)
2023-11-24 09:03:14     at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:109)
2023-11-24 09:03:14     at okhttp3.internal.cache.CacheInterceptor.intercept(CacheInterceptor.kt:95)
2023-11-24 09:03:14     at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:109)
2023-11-24 09:03:14     at okhttp3.internal.http.BridgeInterceptor.intercept(BridgeInterceptor.kt:83)
2023-11-24 09:03:14     at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:109)
2023-11-24 09:03:14     at okhttp3.internal.http.RetryAndFollowUpInterceptor.intercept(RetryAndFollowUpInterceptor.kt:76)
2023-11-24 09:03:14     at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:109)
2023-11-24 09:03:14     at okhttp3.internal.connection.RealCall.getResponseWithInterceptorChain$okhttp(RealCall.kt:201)
2023-11-24 09:03:14     at okhttp3.internal.connection.RealCall.execute(RealCall.kt:154)
2023-11-24 09:03:14     at org.apache.nifi.processors.elasticsearch.AbstractElasticsearchHttpProcessor.sendRequestToElasticsearch(AbstractElasticsearchHttpProcessor.java:269)
2023-11-24 09:03:14     at org.apache.nifi.processors.elasticsearch.QueryElasticsearchHttp.onTrigger(QueryElasticsearchHttp.java:352)
2023-11-24 09:03:14     at org.apache.nifi.processor.AbstractProcessor.onTrigger(AbstractProcessor.java:27)
2023-11-24 09:03:14     at org.apache.nifi.controller.StandardProcessorNode.onTrigger(StandardProcessorNode.java:1361)
2023-11-24 09:03:14     at org.apache.nifi.controller.tasks.ConnectableTask.invoke(ConnectableTask.java:247)
2023-11-24 09:03:14     at org.apache.nifi.controller.scheduling.AbstractTimeBasedSchedulingAgent.lambda$doScheduleOnce$0(AbstractTimeBasedSchedulingAgent.java:59)
2023-11-24 09:03:14     at org.apache.nifi.engine.FlowEngine$2.run(FlowEngine.java:110)
2023-11-24 09:03:14     at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
2023-11-24 09:03:14     at java.base/java.util.concurrent.FutureTask.run(Unknown Source)
2023-11-24 09:03:14     at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknown Source)
2023-11-24 09:03:14     at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
2023-11-24 09:03:14     at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
2023-11-24 09:03:14     at java.base/java.lang.Thread.run(Unknown Source)
2023-11-24 09:03:14 Caused by: java.net.ConnectException: Connection refused (Connection refused)
2023-11-24 09:03:14     at java.base/java.net.PlainSocketImpl.socketConnect(Native Method)
2023-11-24 09:03:14     at java.base/java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
2023-11-24 09:03:14     at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
2023-11-24 09:03:14     at java.base/java.net.AbstractPlainSocketImpl.connect(Unknown Source)
2023-11-24 09:03:14     at java.base/java.net.SocksSocketImpl.connect(Unknown Source)
2023-11-24 09:03:14     at java.base/java.net.Socket.connect(Unknown Source)
2023-11-24 09:03:14     at okhttp3.internal.platform.Platform.connectSocket(Platform.kt:128)
2023-11-24 09:03:14     at okhttp3.internal.connection.RealConnection.connectSocket(RealConnection.kt:295)