CODEWITHSUNDEEP
cmqttesp32platformio
Dauggie
Dauggie

Reputation: 35

ESP-32 can't connect to MQTT broker: mqtt_client: Error network response

I am trying to connect my ESP32 which runs using the ESP-IDF framework to MQTT. I have imported this MQTT library successfully and have set up the configuration to look like this:

static void mqtt_app_start(void)
{
    const esp_mqtt_client_config_t mqtt_cfg = {
        // .host = "m15.cloudmqtt.com",
        .uri = "mqtt://rxarkckf:[email protected]:10793", // uri in the format (username:password@domain:port)
        // .host = "m15.cloudmqtt.com", // config with host, port, user, password seperated
        // .port = 10793,
        // .username = "rxarkckf",
        // .password = "smNb81Ppfe7T",

        .event_handle = mqtt_event_handler,
        // .user_context = (void *)your_context
    };

    esp_mqtt_client_handle_t client = esp_mqtt_client_init(&mqtt_cfg);
    esp_mqtt_client_start(client);
}

I call mqtt_app_start(); in my app_main function. After uploading the code my ESP-32 doesn't connect to the MQTT broker and outputs this:

␛[0;32mI (12633410) MQTT_CLIENT: Sending MQTT CONNECT message, type: 1, id: 0000␛[0m
␛[0;31mE (12633710) MQTT_CLIENT: Error network response␛[0m
␛[0;32mI (12633710) MQTT_CLIENT: Error MQTT Connected␛[0m
␛[0;32mI (12633710) MQTT_CLIENT: Reconnect after 10000 ms␛[0m
␛[0;32mI (12633710) MQTT_SAMPLE: MQTT_EVENT_DISCONNECTED␛[0m

I have double checked that the values for the host, username, password, and port are all correct. When I look at the logs on the web interface hosted at cloudmqtt.com, I can see this output:

2018-11-17 03:50:53: New connection from 73.94.66.49 on port 10793.
2018-11-17 03:50:53: Invalid protocol "MQIs�" in CONNECT from 73.94.66.49.
2018-11-17 03:50:53: Socket error on client <unknown>, disconnecting.
2018-11-17 03:51:20: New connection from 73.94.66.49 on port 10793.

Upvotes: 0

Views: 6709

Answers (2)

cesargastonec
cesargastonec

Reputation: 500

The problem is very simple. The library you are using implements the MQTT 3.1 protocol. The server you are trying to connect to implements the MQTT 3.1.1 protocol or higher. As specified in the document (https://www.oasis-open.org/committees/download.php/55095/mqtt-diffs-v1.0-wd01.doc):

4.1 Protocol Name

The Protocol Name is present in the variable header of a MQTT CONNECT control packet. The Protocol Name is a UTF-8 encoded string. In MQTT 3.1 the protocol name is "MQISDP". In MQTT 3.1.1 the protocol name is represented as "MQTT".

For technical info: https://mqtt.org/mqtt-specification/

Upvotes: 0

Jens
Jens

Reputation: 1

I had similar experience using mosquitto.

Adding this line to mqtt_config.h made my mqtt working.

#define CONFIG_MQTT_PROTOCOL_311

I think the more correct way to set this configuration is in sdkconfig.h, either manually or using "make menuconfig"

Upvotes: 0

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