Failed to convert source to a json string – 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.

Briefly, this error occurs when Elasticsearch is unable to convert the source data to a JSON string. This could be due to issues with the data format or issues with the way the data is being provided to Elasticsearch. You will need to resolve the issue to create a successful index.

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 ” failed to convert source to a json string ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: source and search.

Log Context

Log “failed to convert source to a json string”classname  is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

return null;
 try {
 return XContentHelper.convertToJson(getSourceRef(); false);
 } catch (IOException e) {
 throw new ElasticsearchParseException("failed to convert source to a json string");


See how you can use AutoOps to resolve issues

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