Using AWS OpenSearch - am I able to adjust cluster settings - particularly our watermark

Tried and got

curl -H 'Content-Type: application/json' -k -u 'user:pass' -XPUT 'https://localhost:9902/_cluster/settings' -d '
{
  "persistent": {
    "cluster.routing.allocation.disk.watermark.low": "85%",
    "cluster.routing.allocation.disk.watermark.high": "90%",
    "cluster.routing.allocation.disk.watermark.flood_stage": "95%",
    "cluster.info.update.interval": "1m"
  }
}'
➜  prod ./adjust-settings.sh
{"Message":"Your request: '/_cluster/settings' payload is not allowed."}%