connection error: { [MongoError: auth failed] name: 'MongoError', ok: 0, errmsg: 'auth failed', code: 18 }

2015-06-13T15:10:09.863-0400 I ACCESS [conn8] authenticate db: mydatabase { authenticate: 1, user: "user", nonce: "xxx", key: "xxx" } 2015-06-13T15:10:09.863-0400 I ACCESS [conn8] Failed to authenticate user@mydatabase with mechanism MONGODB-CR: AuthenticationFailed UserNotFound Could not find user user@mydatabase

{
    "_id" : "mydatabase.user",
    "user" : "user",
    "db" : "mydatabase",
    "roles" : [
        {
            "role" : "readWrite",
            "db" : "mydatabase"
        }
    ]
}

mongoose.connect('mongodb://user:password@host:port/mydatabase');

mongoose.connect('mongodb://host:port/mydatabase',{user: 'user',pass: 'password'});

mongo mydatabase -u user -p password

db.createUser({
  user: "user",
  pwd: "password",
  roles: [
    { role: "readWrite", db: "mydatabase" }
  ]
});