Steps to reproduce:

1. Create a connector to stream item values, only change URL to for example http://elasticsearch:9200/zabbix-data-stream/_doc other fields left default
2. Create datastream in elasticsearch

Result:
Data is injected in Elasticsearch, elasticsearch response with HTTP 201 (Created [RFC7231, Section 6.3.2]).

Zabbix logs repond:  Response code "201" did not match any of the required status codes "200"

Expected:
As HTTP 201 response is a valid successful response, zabbix should not complain about the response. 

Note: Also response 202 Accepted [RFC7231, Section 6.3.3] is a valid response.