MQTTnet disconnects from Azure IoT Hub on message publish

Question

I am trying to subscribe MQTT messages in Azure IoT Hub. I am able to publish message using MQTTNet library but when I create subscriber to receive message from IoT hub then connection gets disconnected once message is published to the IoT hub.

I have tried to publish message from separate application and VS code extension, in both cases subscriber gets disconnected on message published.

I am using following code for subscriber

Console.WriteLine("Starting Subscriber.....");
//create subscriber client
var mqttFactory = new MqttFactory();

var mqttClient = mqttFactory.CreateMqttClient();
var mqttClientOptions = new MqttClientOptionsBuilder()
                     .WithClientId("<Device-Id>")
                        .WithTcpServer("<IoTHub>.azure-devices.net", 8883)
                        .WithCredentials("<IoTHub>.azure-devices.net/<Device-Id>/api-version=2018-06-30", "SharedAccessSignature")
                        .WithTls(new MqttClientOptionsBuilderTlsParameters() { UseTls = true })
                        .WithCleanSession()
                    .Build();

mqttClient.ConnectedAsync += async (MqttClientConnectedEventArgs arg) =>
{
    Console.WriteLine("Connected");
};

mqttClient.DisconnectedAsync += async (MqttClientDisconnectedEventArgs arg) =>
{
    Console.WriteLine("Disconnected");
};

mqttClient.ApplicationMessageReceivedAsync += async (MqttApplicationMessageReceivedEventArgs arg) =>
{
    Console.WriteLine("Message received");
};

var result = mqttClient.ConnectAsync(mqttClientOptions, CancellationToken.None).GetAwaiter().GetResult();

var mqttSubscribeOptions = mqttFactory.CreateSubscribeOptionsBuilder()
    .WithTopicFilter(
        f =>
        {
            f.WithTopic("devices/<Device-Id>/messages/events/");
        })
    .Build();

var r = mqttClient.SubscribeAsync(mqttSubscribeOptions, CancellationToken.None).GetAwaiter().GetResult();

Console.WriteLine("MQTT client subscribed to topic.");

Console.WriteLine("Press enter to exit.");
Console.ReadLine();

When I run this code and publish message then I get following output

Instead of receiver event, mqtt disconnect event fires. I am using 4.1.4.563 version of MQTTnet library. Any help would be gratefully appreciated, thanks!

Answer 1

You are subscribing to a custom topic. See here similar question.

Device can subscribe to devices/{device_id}/messages/devicebound/#