xamarin mqtt not subscriving to messages - xamarin.forms

Question

I have an mqtt broker in an android APP. I can connect to it from my nodeMCU (microPython) and publish and check messages.
I created an android app using Xamarin. Forms and I create a MQTT client like this :
IMqttClient client;
string topic = "test/msg";
var configuration = new MqttConfiguration();
this.client = await MqttClient.CreateAsync("192.168.110.51", configuration);
this.client.Disconnected += (o, e) => Debug($"disconnection (at client level)! {e.Message} and {e.Reason} ");
var state = await client.ConnectAsync(new MqttClientCredentials(clientId: "tester"));
await client.SubscribeAsync(topic, MqttQualityOfService.AtLeastOnce);
client
.MessageStream
.Subscribe(msg => Debug($"Message received in topic"));
I created a button that does this :
var msg = new MqttApplicationMessage(topic, Encoding.UTF8.GetBytes("HELO"));
await client.PublishAsync(msg, MqttQualityOfService.AtLeastOnce);
I then test the whole environment and it happens that when I publish from Xamarin I can read the HELO at the MCU, but not from the Xamarin (that's subscribed to the channel) and If I publish from the nodeMCU I can read from other nodeMCU but NOT from the Xamarin.
I tried subscribing to "#" to listen to anything, anyhow nothing appeared.
Any suggestion ??
UPDATE 1:
I tested with MQTT.fx and I can read all messages outputted from both nodeMCU (python) and Phone (Xamarin) and I can also publish messages and nodeMCU (Python) will receive them whilst Xamarin will not notice :(