MQTTnet and AWS IOT - can connect and publish, can't subscribe

Question

I am trying to write a POC using MQTTnet and AWS IOT. I can successfully connect and publish messages, but as soon as I subscribe the connection is closed with MqttClientDisconnectedException

topic is "vin/my-vin"
MQTTnet 4.2.1.781
.NET 7 - console app

connect - works

var mqttFactory = new MqttFactory();

mqttClient = mqttFactory.CreateMqttClient();

var mqttClientOptions = new MqttClientOptionsBuilder()
                    .WithWebSocketServer(signedRequestUrl)
                    .Build();

await mqttClient.ConnectAsync(mqttClientOptions);

publish - works

var applicationMessage = new MqttApplicationMessageBuilder()
            .WithTopic(topic)
            .WithPayload("test")
            .Build();

var resp = await mqttClient.PublishAsync(applicationMessage);

subscribe - fails with MqttClientDisconnectedException

var result = await mqttClient.SubscribeAsync(new MqttTopicFilterBuilder().WithTopic(topic).Build());

I've tried numerous different options when creating the client and calling subscribe, and the result is always the same

I believe another one of our devs has been able to get both publish and subscribe working in a web app with a javascript library, but I don't know the details (its the weekend)

MQTT is new to me so I might be missing something obvious. Any ideas what I'm doing wrong?

MQTTnet and AWS IOT - can connect and publish, can't subscribe

0 Answers0