# \[logstash.outputs.elasticsearch\] An unknown error occurred sending a bulk request to Elasticsearch

**URL:** <https://discuss.elastic.co/t/logstash-outputs-elasticsearch-an-unknown-error-occurred-sending-a-bulk-request-to-elasticsearch/145435>\
**Category:** Logstash\
**Created:** [August 21, 2018, 5:10pm UTC](https://discuss.elastic.co/t/logstash-outputs-elasticsearch-an-unknown-error-occurred-sending-a-bulk-request-to-elasticsearch/145435 "2018-08-21T17:10:25Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![perryparktung](https://avatars.discourse-cdn.com/v4/letter/p/d78d45/32.png) [@perryparktung](https://discuss.elastic.co/u/perryparktung)\
**Post date:** [August 21, 2018, 9:25pm UTC](https://discuss.elastic.co/t/logstash-outputs-elasticsearch-an-unknown-error-occurred-sending-a-bulk-request-to-elasticsearch/145435/2 "2018-08-21T21:25:20Z")

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Figured. in the logstash config file I used "copy" function under "mutate", while I actually need to use "add\_field" function.  
details in [LogStash::Json::GeneratorError when using mutate copy @timestamp](https://discuss.elastic.co/t/logstash-json-generatorerror-when-using-mutate-copy-timestamp/119256)

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