Unable to create new indices #406

Hello All am unable to create new indices in elassandra 6.8.4.13. OS Ubuntu 18.04.
When I hit PUT command it just stuck. I have to cancel it manually. But data write/read in already created indices is working fine. Even though I can't change any cluster setting with PUT command.

ie. to change search strategy for existing indices, deleting existing indices, create new index, change mapping. I am unable to perform these operations.
ubuntu@node-1:~$ curl http://x.x.x.x:9200/_cluster/health?pretty
{
"cluster_name" : "prod",
"status" : "green",
"timed_out" : false,
"number_of_nodes" : 9,
"number_of_data_nodes" : 9,
"active_primary_shards" : 2214,
"active_shards" : 2214,
"relocating_shards" : 0,
"initializing_shards" : 0,
"unassigned_shards" : 0,
"delayed_unassigned_shards" : 0,
"number_of_pending_tasks" : 1,
"number_of_in_flight_fetch" : 0,
"task_max_waiting_in_queue_millis" : 0,
"active_shards_percent_as_number" : 100.0
}

Thanks in advance