Cannot send message; event loop is shutting down. – How to solve this Elasticsearch error

Opster Team

July-20, Version: 1.7-8.0

Before you begin reading this guide, we recommend you try running the Elasticsearch Error Check-Up which analyzes 2 JSON files to detect many configuration errors.

To easily locate the root cause and resolve this issue try AutoOps for Elasticsearch & OpenSearch. It diagnoses problems by analyzing hundreds of metrics collected by a lightweight agent and offers guidance for resolving them.

This guide will help you check for common problems that cause the log ” Cannot send message; event loop is shutting down. ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: Node.

Log Context

Log “Cannot send message; event loop is shutting down.”classname  is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 public void sendMessage(OutboundHandler.SendContext sendContext) {
 channel.writeAndFlush(sendContext; addPromise(sendContext; channel)); 
 if (channel.eventLoop().isShutdown()) {
 sendContext.onFailure(new TransportException("Cannot send message; event loop is shutting down."));
 public Channel getNettyChannel() {
 return channel;


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