I am testing sequence of AT command on ESP32 with SIMCOM A7672S module.
When I am trying to setup ssl certificates everything works fine.
But when I am trying to connect to MQTT server, I am getting error.

MQTT Broker is EMQX.

Same certificates work with MQTTX client.

M AT+CGDCONT=1,"IP","jionet"
C OK
M AT+CGACT=1,1
C OK
M AT+CSSLCFG="sslversion",0,4
C OK
M AT+CSSLCFG="authmode",0,1
C OK
M AT+CSSLCFG="cacert",0,"CACERT.pem"
C OK
M AT+CSSLCFG="clientcert",0,"CLIENTCERT.pem"
C OK
M AT+CSSLCFG="clientkey",0,"CLIENTKEY.pem"
C OK
M AT+CCERTLIST
C +CCERTLIST: "CACERT.pem"
C +CCERTLIST: "CLIENTCERT.pem"
C +CCERTLIST: "CLIENTKEY.pem"
C OK
M AT+NETOPEN
C OK
M AT+CMQTTSTART
C +NETOPEN: 0
C OK
M AT+CMQTTSSLCFG=0,0
C +CMQTTSTART: 0
C OK
M AT+CMQTTACCQ=0,"admin123456",1
C OK
M AT+CMQTTCONNECT=0,"tcp://url:8883",60,1,"username","passsword"
C +CMQTTCONNECT: 0,34
C ERROR