@brossingo I have encountered this. (mainly when using incorrect firmware). You should also include the stacktrace, so we can see where in umqtt it is occuring. T

@brossingo what was the output if the program when you ran it? Checking the return value of client.connect() might yield useful information.

@randomrnti Figured out my issue was due to the AWS policy only allowing certain clients for the iot:Connect policy. Changing it to the wildcard * fixed my issue. Another issue though is I can only get it working for Wifi. The moment I attempt this on NB-IoT I'm getting the following errors: AWSIoTMQTTClient Socket create error: [Errno -78] MBEDTLS_ERR_NET_SEND_FAILED simple.py Traceback (most recent call last): File "main.py", line 90, in <module> File "main.py", line 79, in run File "/flash/lib/simple.py", line 56, in connect OSError: [Errno 113] ECONNABORTED This again is on the connect action and I've tried with connecting using both the IP Address and it's domain name.

@matt You should consider checking the connection state. ( Various brokers may time the connection out at the other end.) and then possibly explicitly closing the connection and re-connecting. I am using the core of the AWS MQTT package to talk to Losant and had to deal with the connection status and reconnections. That package maintains the connection in a seperate thread and the library doesn't clean up well so it needed some hacking. I have found the robust and simple implementations also needs some tweaking to be reliable on ESP8266 so it doesn't surprise me. You may even find it makes sense to disconnect after sending a message and then reconnecting later. Have a look at what the default timouts and the inactivity timeouts are set for the MQTT service you are talking to,

This is the server I am using. You can get a trial account. I am trying to either use the MQTT Websockets or MQTT TCP/IP with mosquito as the broker.

Hello, i am trying very hard to subscribe to a topic and actually receive something. I am using the integrated client on the AWS side to debug. i am observing that i am successful when it comes to publishing topics. It works well. If i subscribe to a topic i just do not receive anything at all. I have tried with both simple and the guide in the pycom documentation. I suspect at this point a misconfiguration from the side of AWS. I have permission in my policy to subscribe to any resource. Subscription itself works. No messages are ever displayed though. Callback is never called. any help is appreciated!