Akka cluster not waiting for all nodes to be up

I am starting an akka cluster, and in the config I have specified

min-nr-of-members = 3

however, when I start the main application - the cluster starts without any of the members having joined.

This is the code below to get new nodes to joint the cluster.

        List<Address> addressList = getSeedNodes(config, config.getInt("akka.remote.artery.canonical.port"));
        Cluster.get(system).manager().tell(new JoinSeedNodes(addressList));

List<Address> addressList looks like [akka://liam@hostname:2551, akka://liam@hostname:2552] The main node is hostname:2550, what am I missing?