Could not parse http response expected a header name but found – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-7.15

Briefly, this error occurs when Elasticsearch expects a header name in the HTTP response but finds an unexpected value or format. This could be due to a malformed HTTP response or a bug in the client or server. To resolve this issue, you can: 1) Check the format of your HTTP response to ensure it’s correctly structured. 2) Update your Elasticsearch client or server to the latest version to fix any potential bugs. 3) Debug your application to identify any issues in the code that may be causing the malformed response.

This guide will help you check for common problems that cause the log ” could not parse http response. expected a header name but found [{}] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin, response.

Log Context

Log “could not parse http response. expected a header name but found [{}]” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 String headerName = null;
 while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
 if (token == XContentParser.Token.FIELD_NAME) {
 headerName = parser.currentName();
 } else if (headerName == null){
 throw new ElasticsearchParseException("could not parse http response. expected a header name but found [{}] " +
 "instead"; token);
 } else if (token.isValue()) {
 headers.put(headerName; new String[] { String.valueOf(parser.objectText()) });
 } else if (token == XContentParser.Token.START_ARRAY) {
 List values = new ArrayList<>();


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