EG95 issues with MQTT


I’m having some trouble connecting to an MQTT server using AT commands. My hardware is a RAK7243 with an EG95 module.

Everything works fine until the AT+QMTOPEN command. This command always outputs “0,3,” which indicates “Failed to activate PDP” (see page 14 of the Quectel EG9x MQTT Application Note V1.1). Before using AT+QMTOPEN, I tried activating PDP with AT+CGACT=1,1 without success.

Here’s some potentially relevant information:

  • The AT+QMTOPEN command I’m using is: AT+QMTOPEN=0,"",1883 (always returns 0,3).
  • AT+CGDCONT returns five contexts with all zeros for the IP address (I expected an IP address assigned by the network provider).
  • After using AT+CGDCONT, the command CGPADDR returns an invalid IP address that appears very large.
  • AT+COPS returns: +COPS: 0,0,"T-Mobile",7 (which I believe is okay).
  • AT+CREG returns: 0,1 (also okay).
  • AT+QPING=1,"" always returns “561” (unclear if successful ping).
  • Calling functionality works perfectly.

Do you have any ideas what might be causing this issue? Could it be possible that my SIM card lacks a data plan or service?

Thank you!

Welcome to RAK forum @psparodi ,

I have limited experience on MQTT of BG96 but might be related to EG95.

Before I enable MQTT, I make sure that the internet connection is established with the correct APN using AT+QICSGP and AT+QIACT. Maybe something you can double check.

Hello @carlrowan,

Thank you for your reply.

The command “AT+QICSGP=1” is returning:

+QICSGP: 1,"","","",0

However, “AT+QIACT?” returns ERROR. Based on my understanding of the TCP/IP Application Notes, this command should list currently active PDP contexts.

Do these responses indicate that there’s no data connection?

Thank you,

Hi Pablo,

AT+QIACT must be ok otherwise, you cannot establish a connection. Few things we can try to check.

  1. Antenna connection?
  2. Does it have cellular data?
  3. Maybe check also power source?
  4. Is APN configured correctly?

Hi @carlrowan

I will check all that.

Thank you for your help!.