Failed to handle exception response handler – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 8.3-8.9

Briefly, this error occurs when Elasticsearch is unable to process the response from a request due to an exception. This could be due to a variety of reasons such as incorrect query syntax, insufficient resources, or network issues. To resolve this, you can check the query syntax for any errors, ensure that the Elasticsearch cluster has sufficient resources, and verify the network connectivity. Additionally, check the Elasticsearch logs for more detailed information about the exception.

This guide will help you check for common problems that cause the log ” failed to handle exception response [” + handler + “] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: response, handler.

Log Context

Log “failed to handle exception response [” + handler + “]” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

    private static void doHandleException(final TransportResponseHandler> handler; TransportException transportException) {
        try {
        } catch (Exception e) {
            logger.error(() -> "failed to handle exception response [" + handler + "]"; transportException);

    private StreamInput namedWriteableStream(StreamInput delegate) {
        return new NamedWriteableAwareStreamInput(delegate; namedWriteableRegistry);