magento2 – Suddenly stop working elastic search, Error message : Couldn’t connect to host, Elasticsearch down?

I am stuck on this issue my code suddenly stops working not able to find the root cause of any idea regarding this. Earlier it was working fine. Kindly help. I have checked the all configuration are correct.

Fatal error:  Uncaught ElasticaExceptionConnectionHttpException: Couldn't connect to host, Elasticsearch down? in /data/docroot/magento/vendor/ruflin/elastica/lib/Elastica/Transport/Http.php:186
Stack trace:
#0 /data/docroot/magento/vendor/ruflin/elastica/lib/Elastica/Request.php(171): ElasticaTransportHttp->exec(Object(ElasticaRequest), Array)
#1 /data/docroot/magento/vendor/ruflin/elastica/lib/Elastica/Client.php(662): ElasticaRequest->send()
#2 /data/docroot/magento/vendor/ruflin/elastica/lib/Elastica/Search.php(461): ElasticaClient->request('elasticdata/...', 'GET', Array, Array)
#3 /data/docroot/magento/fetch_all_data.php(142): ElasticaSearch->search(Object(ElasticaQuery))
#4 {main}
  thrown in /data/docroot/magento/vendor/ruflin/elastica/lib/Elastica/Transport/Http.php on line 186