Troubleshooting MQTT Connection Issue with MC60 Module: '+QMTOPEN: 0,-1' Error

Hello everyone,

I’m currently working with an MC60 module and attempting to establish a connection with the ‘test.mosquitto.org’ MQTT server on port 8883 using CA authentication. However, I’m encountering an issue with the error message +QMTOPEN: 0,-1. I’ve followed the steps outlined in this guide: Quectel-AT-Examples.

And here my log file

AT+QMTCFG="SSL",0,1,2

OK
AT+QSECWRITE="RAM:cacert.pem",1452,100

CONNECT

+QSECWRITE: 1452,7710

OK
AT+QSECREAD="RAM:cacert.pem"

+QSECREAD: 1,7710

OK
AT+QSSLCFG="cacert",2,"RAM:cacert.pem"

OK
AT+QSSLCFG="seclevel",2,2

OK
AT+QSSLCFG="sslversion",2,4

OK
AT+QSSLCFG="ciphersuite",2,"0xFFFF"

OK
AT+QSSLCFG="ignorertctime",1

OK
AT+CPIN?

+CPIN: READY

OK
AT+CREG?

+CREG: 0,1

OK
AT+CGREG?

+CGREG: 0,1

OK
AT+QIMODE=0

OK
AT+QICSGP=1,"INTERNET"

OK
AT+QIREGAPP

OK
AT+QICSGP?

+QICSGP: 1

OK
AT+QIACT

OK
AT+QILOCIP

10.38.184.159
AT+QMTOPEN=0,"test.mosquitto.org","8883"

OK

+QMTOPEN: 0,-1

Additionally, I’ve observed that when attempting to connect without using SSL on port 1883, I can successfully establish a connection.

I would greatly appreciate any insights or guidance on resolving the ‘+QMTOPEN: 0,-1’ error and successfully establishing a connection with the MQTT server.