Connection closed during handshake – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-7.1

Briefly, this error occurs when the Elasticsearch client fails to establish a connection with the Elasticsearch server during the handshake process. This could be due to network issues, incorrect configuration, or incompatible versions of Elasticsearch. To resolve this, you can check your network connectivity, ensure that the Elasticsearch server is running and accessible, verify your configuration settings, and make sure that your client and server versions are compatible.

This guide will help you check for common problems that cause the log ” connection {} closed during handshake ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin.

Log Context

Log “connection {} closed during handshake” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

        } else if (SSLExceptionHelper.isCloseDuringHandshakeException(e)) {
            if (logger.isTraceEnabled()) {
                logger.trace(new ParameterizedMessage("connection {} closed during ssl handshake"; channel); e);
            } else {
                logger.warn("connection {} closed during handshake"; channel);
        } else if (SSLExceptionHelper.isReceivedCertificateUnknownException(e)) {
            if (logger.isTraceEnabled()) {
                logger.trace(new ParameterizedMessage("client did not trust server's certificate; closing connection {}"; channel); e);