High Search Rejected

Hi,

My ELasticsearch thread pool search has very high rejected ration. I have sufficient 72 CPU nodes.

node_name name active queue rejected
ES10 search 7 0 22703
ES07 search 0 0 0
ES08 search 3 0 13108
ES00 search 3 0 9551
ES11 search 3 0 19003
ES09 search 5 0 21755
ES03 search 6 0 20115
ES12 search 4 0 10777
ES05 search 0 0 0
ES06 search 0 0 0
ES02 search 8 0 20093
ES01 search 6 0 20370

Not sure why its high, I saw cpu is good and query cache. Search queries are taking time.

How much RAM does the nodes have? How much data does each node hold? What type of storage are you using? Which version of Elasticsearch are you using?

I'm using elastic cloud . here is the complete details
Total
15.29 TB storage
522 GB RAM
71.4 vCPU

version of elasticsearch is 7.13.2

What is the full output of the cluster stats API? What kind of load is the cluster under?