Rejected execution of org.elasticsearch.transport.TransportService

I am getting the below error in my environment. Initially td-agent to push the logs for some time, but getting the below after a moment. Any help is greatly helpful...
Did a lot of research but couldnt find the solution anywhere

"error"=>{"type"=>"es_rejected_execution_exception", "reason"=>"rejected execution of org.elasticsearch.transport.TransportService$7@41fd900a on EsThreadPoolExecutor[bulk, queue capacity = 200, org.elasticsearch.common.util.concurrent.EsThreadPoolExecutor@6462bef6[Running, pool size = 8, active threads = 8, queued tasks = 247, completed tasks = 9108068]]"}}}, {"index"=>{"_index"=>"test-logs", "_type"=>"fluentd", "_id"=>"AV0T51EQYjB5DZCGbKpI", "status"=>429, "error"=>{"type"=>"es_rejected_execution_exception", "reason"=>"rejected execution of org.elasticsearch.transport.TransportService$7@41fd900a on EsThreadPoolExecutor[bulk, queue capacity = 200, org.elasticsearch.common.util.concurrent.EsThreadPoolExecutor@6462bef6[Running, pool size = 8, active threads = 8, queued tasks = 247, completed tasks = 9108068]]"}}}]}

Your client (I don't know what it is) needs to slow down and retry when elasticsearch seems to be overloaded.
May be adjust the size of a single bulk request?

How many documents are you sending per bulk request?

Here the bulk queue size is 200 but you tried to queue more than that.