Failed to send bad request response – How to solve this OpenSearch error

Opster Team

Aug-23, Version: 1-2.9

Before you dig into reading this guide, have you tried asking OpsGPT what this log means? You’ll receive a customized analysis of your log.

Try OpsGPT now for step-by-step guidance and tailored insights into your OpenSearch operation.

Briefly, this error occurs when OpenSearch fails to send a response to a client due to a malformed or invalid request. This could be due to incorrect syntax, unsupported parameters, or a request that exceeds server limits. To resolve this issue, you should first verify the syntax and parameters of your request. Ensure they are correctly formatted and supported by your OpenSearch version. If the request is large, consider breaking it down into smaller parts. Also, check your server’s settings to ensure it can handle the size and complexity of your requests.

For a complete solution to your to your search operation, try for free AutoOps for Elasticsearch & OpenSearch . With AutoOps and Opster’s proactive support, you don’t have to worry about your search operation – we take charge of it. Get improved performance & stability with less hardware.

This guide will help you check for common problems that cause the log ” failed to send bad request response ” to appear. To understand the issues related to this log, read the explanation below about the following OpenSearch concepts: response, request, rest.

Log Context

Log “failed to send bad request response” classname is
We extracted the following from OpenSearch source code for those seeking an in-depth context :

            channel.sendResponse(new BytesRestResponse(channel; BAD_REQUEST; e));
        } catch (final IOException e) {
            if (cause != null) {
            logger.warn("failed to send bad request response"; e);
            channel.sendResponse(new BytesRestResponse(INTERNAL_SERVER_ERROR; BytesRestResponse.TEXT_CONTENT_TYPE; BytesArray.EMPTY));

    private void dispatchRequest(RestRequest request; RestChannel channel; RestHandler handler) throws Exception {


How helpful was this guide?

We are sorry that this post was not useful for you!

Let us improve this post!

Tell us how we can improve this post?

Get expert answers on Elasticsearch/OpenSearch