BG96 MQTT publish command timout AT+QMTPUB


I am using the BG96 and trying to post some data on a custom MQTT broker. It works fine for a few MQTT publish but for some reason, I happen to have a QMTPUB command that doesn’t have response from the modem.

I cannot find an answer to why the modem never replies to the command, even to tell me that it timed out.

I tested the following command with various parameters but never made it work properly:


I am sure that my custom timeout is longer than the command timeout (30s_Timout*5_retry = 150s, my timeout is 180s).

For reference here is the file with all the logs until the problem happens

Debug_BG96_post_support.txt (7.6 KB)

Thank you for your answer

Best regards,

@Aug are you making sure before publish that PDP context is activated?

AT+QIACT? gives you IP address when it is active.

In my BG95-M3 application, when the PDP context is dropped due to network disconnection or data call disconnection, there’s a delay before anything is received in the mqtt_connection_callback. This delay seems to be equal to the keep-alive timeout.

I’ve observed that even after PDP disconnection, the MQTT connection remains intact (AT+QMTCONN? returns OK) until the keep-alive timeout. I believe this might be what’s happening with your situation as well.

Perhaps you could try the following:

  1. Verify if the data call is connected before publishing.
  2. Decrease the keep-alive timeout (try 10).
  3. Subscribe to a topic and continuously publish on that topic to ensure MQTT is functioning bidirectionally.