how to fix replica set error I am getting this error 

{ "ok" : 0, "errmsg" : "server is not running with --replSet" }


when I run the command on windows cmd

rs.initiate( { _id : "repl1", members: [ { _id : 0, host : "mongodb0.example.net:27017" } ] })


I changed it to

rs.initiate( { _id : "repl1", members: [ { _id : 0, host : "localhost:27017" } ] })


but still have same error

how can I fix this issue?
Simple, start your replica sets nodes with --replSet xxx (where xxx is your replica set name) -parameter. If you use config files, then replication.replSetName: xxx

Read here how to configure/deploy replica set.