Have the Failover check "down-after-milliseconds" Sentinel attribute to be Customer configurable

The down-after-milliseconds is the time in milliseconds an instance should not be reachable (either does not reply to our PINGs or it is replying with an error) for a Sentinel starting to think it is down.

Currently we are unable to configure/change this attribute from our side and when we had some stability issues, IBM helped with updating the failover check from 30 seconds to 5 mins.

When we tried running through the commandline, it threw a 422 status code exception. Can this be checked and made customer configurable please?

FAILED Error response from server. Status code: 422; message: {"errors":{"configuration.down-after-milliseconds":["not supported"]}}