Failed to notify listeners – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-8.9

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Briefly, this error occurs when Elasticsearch fails to notify its listeners about a certain event. This could be due to a network issue, a problem with the listener itself, or a bug in the Elasticsearch code. To resolve this issue, you can try restarting Elasticsearch, checking the network connection, or updating Elasticsearch to the latest version. If the problem persists, you may need to debug the listener to identify and fix the issue.

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

Log Context

Log “Failed to notify listeners” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

        if (listeners != null) {
            try {
                ActionListener.onFailure(listeners; failure);
            } catch (Exception ex) {
                assert false : new AssertionError(ex);
                logger.warn("Failed to notify listeners"; ex);

    private static  void completeListenersIgnoringException(@Nullable List> listeners; T result) {


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