"Failed to find a plan!" adding a shard in Ops Manager

Hi, i have a cluster(cl1) configured with two shards(each one with three nodes, p-s-s), now i like to add a replica set(rset2) as part of the cluster(cl1). go to process->cluster(cl1)->modify and add a new shard ( with each member of the rset2 ), when save the config, its showing errors like…

.. No plan could be found - not in goal state because of:
[All the following are true: 
    ['desiredState.ReplSetConf' != <nil> ('desiredState.ReplSetConf' = ReplSetConfig{id=shard_2,version=0,configsvr=false,protocolVersion=1,forceProtocolVersion=false,writeConcernMajorityJournalDefault=,members={id:0,HostPort:centos81:27137,ArbiterOnly:falsePriority:1,Hidden:false,SlaveDelay:0,Votes:1,Tags:map[]},{id:1,HostPort:centos82:27138,ArbiterOnly:falsePriority:1,Hidden:false,SlaveDelay:0,Votes:1,Tags:map[]},{id:2,HostPort:centos72:27139,ArbiterOnly:falsePriority:1,Hidden:false,SlaveDelay:0,Votes:1,Tags:map[]},settings=map[]})]
    ['currentState.ReplSetConf.Id' != 'desiredState.ReplSetConf.Id' : (repl2) vs. (shard_2)]

i don’t understand why those errors are appearing, the replica set is working well, thanks for the explanation