NATS Only receiving messages after subscription

Question

I'm trying to communicate with a NATs server in the cloud with the "github.com/nats-io/go-nats" package.

I`m setting it up like this:

nc, err := nats.Connect(natsServerAddress)
if err != nil {
    log.Fatal(err)
} else {
    natsConn = nc
}

After that I'm subscribing to the queue:

natsConn.Subscribe(natsRawSimDataQueue, func(m *nats.Msg) {
        fmt.Printf("Received a message: %s\n", string(m.Data))
})

My actual problem is, that the subscription doesn't seem to have an effect. By accident I found out that the subscription handler is triggered after I published at least one message. So when the subscriber's also a publisher it seems to work. Here's the code for the publishing:

// push data to NATS Queue
    natsConn.Publish(natsRawSimDataQueue, []byte("{\"msg\": \"Hello Listener\"}"))

Does anybody know where this issue come from?