Failure to send – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

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Briefly, this error occurs when Elasticsearch is unable to send data to a specified destination. This could be due to network issues, incorrect configuration, or the destination being unavailable. To resolve this, you can check your network connection, ensure the destination is available and correctly configured, and verify that Elasticsearch has the necessary permissions to send data to the destination. If the issue persists, you may need to check the Elasticsearch logs for more detailed error information.

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This guide will help you check for common problems that cause the log ” failure to send ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: .

Log Context

Log “failure to send” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 success = true;
 } catch (Exception e) {
 handler.handleLocalException(new ConnectTransportException(node; "failure to send " + HANDSHAKE_ACTION_NAME; e));
 } finally {
 if (success == false) {
 TransportResponseHandler removed = pendingHandshakes.remove(requestId);
 assert removed == null : "Handshake should not be pending if exception was thrown";


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