Hi @boubou,
How many Elasticsearch nodes do you have? It looks like you have a node communication issue based on this error:
Can you try the remediation steps covered in this StackOverflow thread?
I see you have also raised a similar issue here. I would recommend following @DavidTurner's recommendation in thread to check out the troubleshooting guide,. Please don't post multiple topics for the same issue in future.
Hope that helps!