LWIP MQTT not connecting

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Sébastien Trocherie
评论: Andrew Bierman 2024-3-26,22:52
Hi,
I'm using the STM32F746NG discovery board to connect to the thingspeak MQTT broker.
However I can't connect to the server, i'm using dns to get the server ip adres which I then use in the mqtt_client_connect function.
When I get to the callback function the status is 256 (MQTT_CONNECT_DISCONNECTED).
I've had this problem before with a local MQTT broker (mosquitto 2.0), I was able to solve this problem by installing an older version (mosquitto 1.161a).
I'm using the correct credentials because they work in the mqtt_spy application.
Has anyone had this problem before or a sollution for this problem?
With kind regards
Sébastien

回答(1 个)

Vinod
Vinod 2021-12-31
Could you provide more information - what is the client ID of your device? We may be able to look at the server logs given the client ID to provide you some pointers.
  2 个评论
Andrew Bierman
Andrew Bierman 2024-3-26,18:39
I am having the same problem using lwIP to connect to mqtt3.thingspeak.com. Was there a solution to Sébastien's problem?
I too am using a dns lookup service to get the Thingspeak server ip address (54.81.146.55), and I have tested this and the conection credentials using the MQTTX client app and they work for that app.
The client ID of my device is FDolEB05DQUGNCkiJywCBAA
Andrew Bierman
Andrew Bierman 2024-3-26,22:52
My fault. Apparently, subscribing to a nonexistent channel casues the broker to disconnect. Without doing that it appears to work fine.

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