Trying to connect MQTT broker and try to receive messages from broker and display it into console

Question

I am using a MQTT broker credentials to connect with the MQTT broker but my code always goes to the disconnected block of code. After that it shows me a error message like un-handling exception. I was done lots of research on this topic but i can't find a suitable solution for this issue.

Here is my complete C# code for MQTT broker connection,

using MQTTnet;
using MQTTnet.Client;
using MQTTnet.Client.Options;
using MQTTnet.Extensions.ManagedClient;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace TreonConsole
{
class Program
{
    private static IMqttClient _Client;
    private static IMqttClientOptions _options;
    static void Main(string[] args)
    {
        try
        {
            Console.WriteLine("Starting Subscriber...");

            //Create subscriber client
            var factory = new MqttFactory();
            _Client = factory.CreateMqttClient();
            string clientid= Guid.NewGuid().ToString();

            //Configure options
            _options = new MqttClientOptionsBuilder()
                .WithClientId(clientid)
                .WithTcpServer("b925270106984f21be3ae9d1d48b400fh.s112.eu.hivemq.cloud", 8883)
                .WithCredentials("iap", "Iap321?")
                .WithCleanSession()
                .Build();

            //Handlers
            _Client.UseConnectedHandler(e =>
            {
                Console.WriteLine("Connected successfully with MQTT Brokers.");

                //Subscribe to topic
                _Client.SubscribeAsync(new MqttTopicFilterBuilder().WithTopic("test").Build()).Wait();
            });

            _Client.UseDisconnectedHandler(e =>
            {
                Console.WriteLine("Disconnected from MQTT Brokers.");
            });
            _Client.UseApplicationMessageReceivedHandler(e =>
            {
                Console.WriteLine("Received Application Messages");
                Console.WriteLine($"+Topic={e.ApplicationMessage.Topic}");
                Console.WriteLine($"+Payload={Encoding.UTF8.GetString(e.ApplicationMessage.Payload)}");
                Console.WriteLine($"+Qos={e.ApplicationMessage.QualityOfServiceLevel}");
                Console.WriteLine($"Retaain={e.ApplicationMessage.Retain}");
                Console.WriteLine();

            });

            //actaully connect
            _Client.ConnectAsync(_options).Wait();
            Console.WriteLine("Press Key to Exit");
            Console.ReadLine();
        }
        catch (Exception e)
        {
            Console.WriteLine(e);
            throw;
        }
    }
  }
}

Edit the question to show the actual exception message and any stack trace so we can see exactly how it's failing — hardillb, Jul 14 '21 at 19:29
Also you probably want to change those credentials now you've shared them with the world... — hardillb, Jul 14 '21 at 19:31
Please include details on the exception/error in your question (the following is a guess). Hive MQTT Cloud [only allows secure TLS connections](https://www.hivemq.com/docs/hivemq-cloud/introduction.html#connect-client) (generally port 8883 = MQTT over SSL). This means you will need the [`WithTls` option](https://github.com/chkr1011/MQTTnet/wiki/Client#secure-tcp-connection) see [this answer](https://stackoverflow.com/a/55577356/11810946) for an example. — Brits, Jul 14 '21 at 19:34

score 1 · Answer 1 · answered Jul 14 '21 at 19:35

1

From the look of the HiveMQ docs port 8883 expect to be a TLS secured connection and I don't see where you are setting up the TLS connection in your code.

answered Jul 14 '21 at 19:35

hardillb

54,545
11
67
105

score 1 · Answer 2 · answered Jul 14 '21 at 19:42

1

The problem is that you dont have a secure TLS connection. Add WithTls() option in MqttClientOptionsBuilder.

answered Jul 14 '21 at 19:42

Robert Hansson

166
1
4

Trying to connect MQTT broker and try to receive messages from broker and display it into console

2 Answers2