I am currently integrating the EG800K module in an IoT device and I am experiencing an issue when attempting to establish an MQTT connection using the AT command interface.
The module is able to successfully attach to the network, activate the PDP context, and open a TCP connection to the MQTT broker. However, the command AT+QMTCONN consistently returns ERROR , even though the socket appears to be correctly opened with AT+QMTOPEN .
Below are the module details and test results.
Module: EG800K
Firmware version: EG800KLALCR07A02M04_01.001.01.001
Network status:
-
LTE network attachment successful (
AT+CGATT?returns 1) -
PDP context activated (
AT+QIACT=1) -
Valid IP address assigned
MQTT configuration used:
AT+QMTCFG=“pdpcid”,0,1
AT+QMTCFG=“version”,0,4
AT+QMTCFG=“session”,0,1
AT+QMTCFG=“keepalive”,0,60
AT+QMTCFG=“send/mode”,0,0
AT+QMTCFG=“recv/mode”,0,0,0
MQTT broker test:
AT+QMTOPEN=0,“test.mosquitto.org”,1883
Response:
+QMTOPEN: 0,0
+QMTSTAT: 0,1
However, when sending the connect command:
AT+QMTCONN=0,“alondra151515”
The module immediately returns:
ERROR
Additional tests performed:
- TCP connection test using:
AT+QIOPEN=1,0,“TCP”,“test.mosquitto.org”,1883,0,1
Response:
+QIOPEN: 0,0
Followed shortly by:
+QIURC: “closed”,0
This behavior appears consistent with the server closing the connection because no MQTT CONNECT packet was sent.
Given that TCP connectivity is working but AT+QMTCONN fails immediately with ERROR , it seems the issue may be related to the MQTT client implementation in the current firmware.
Could you please advise:
-
Whether this firmware version has any known MQTT-related issues?
-
If there is a recommended firmware update for stable MQTT functionality on the EG800K?
-
Any additional configuration required before executing
AT+QMTCONN?
If necessary, I can also provide full AT command logs and additional test information.
Thank you for your support.