SIM7600G MQTTS - CMQTTCONNECT: 0,32

[AltayAtaman]

I have been trying to connect my SIM7600G (LilyGo T-PCEI) to my Azure IoT Hub Broker. It gives "CMQTTCONNECT: 0,32" error but it does connect to public brokers such as broker.emqx.io.

Successful connection to public broker:

RDY

+CPIN: READY

SMS DONE

PB DONE
AT+CMQTTSTART
+CMQTTSTART: 0

AT+CCERTDOWN="ca_cert.pem",1358
>-----BEGIN CERTIFICATE-----
<certificate here, multiple lines>
-----END CERTIFICATE-----
OK

AT+CSSLCFG="sslversion",0,4
OK
AT+CSSLCFG="authmode",0,1
OK
AT+CSSLCFG="cacert",0,"ca_cert.pem"
OK
AT+CMQTTSSLCFG=0,0
OK
AT+CMQTTREL=0
OK
AT+CMQTTACCQ=0,"Sim7600_fa7d2288",1
OK
AT+CMQTTCONNECT=0,"tcp://broker.emqx.io:8883",60,1
OK

+CMQTTCONNECT: 0,0

Issue, not being able to connect to Azure IoT:

RDY

+CPIN: READY

SMS DONE

PB DONE
AT+CSSLCFG="sslversion",0,4
OK
AT+CSSLCFG="authmode",0,1
OK
AT+CSSLCFG="ignorelocaltime", 0, 1
OK
AT+CSSLCFG="ciphersuites", 0, 0xFFFF
OK
AT+CSSLCFG="cacert",0,"my_cert.pem"
OK
AT+CSSLCFG="enableSNI", 0, 1
OK
AT+CMQTTSTART
+CMQTTSTART: 0

OK
AT+CMQTTSSLCFG=0,0
OK
AT+CMQTTREL=0
OK
AT+CMQTTACCQ=0,"device_002",1
OK
AT+CMQTTCONNECT=0,"tcp://<my_broker>-devices.net:8883", 60, 1, "<my_broker>.azure-devices.net/device_002/?api-version=2021-04-12", "SharedAccessSignature sr=<my_broker>-devices.net%2Fdevices%2Fdevice_002&sig=********iS=********ZT=********Di********17246=********8"
OK

+CMQTTCONNECT: 0,32

[droidblastnz]

Read my thread gave up due to board firmware https://github.com/Xinyuan-LilyGO/T-SIM7600X/issues/49