Not reachable/healthy Replica Set

Question

I am trying to add one more replica set in existing sets and getting problem in reachability. What are the reasons when we get Not reachable/healthy replica set ?

    "name" : "IP ADDRESS",
    "health" : 0,
    "state" : 8,
    "stateStr" : "(not reachable/healthy)",
    "uptime" : 0,
    "optime" : {
        "t" : 0,
        "i" : 0
    },
    "optimeDate" : ISODate("1970-01-01T00:00:00Z"),
    "lastHeartbeat" : ISODate("2013-06-18T10:52:50Z"),
    "lastHeartbeatRecv" : ISODate("1970-01-01T00:00:00Z"),
    "pingMs" : 0

Answer 1

similar problem i had , the solution was to have a keyfile. http://docs.mongodb.org/manual/tutorial/deploy-replica-set-with-auth/#create-the-key-file-to-be-used-by-each-member-of-the-replica-set