How can be connected by MC60 to MQTT with TLS?

IoT Modules GSM Module
1

I need a secure TLS connection to your MQTT server
I want to use OpenCPU feature
But here I didn’t find anything, is there a sample to connect to the Handshake SSL server?

2

If you look in the program directory, in the “example” folder there is a file called “example_mqtt.c”, which is the instance program of MQTT, you can see if there is anything in this folder that you want

3

dear vincent
thx for replay

I want to handshake certificate ssl
In the example, the connection is wIthtout ssl
For me, it is of type SSL, which has a username and password. The server and the certificate must be handshake
I receive

//<register recv callback,ret = 0
//<RIL is ready
//<SIM Card Status:1
//<state timer start,ret = 0
//<Network State:cgreg = 2
//<Network State:cgreg = 2
//<Network State:cgreg = 2
//<Network State:cgreg = 2
//<Network State:cgreg = 1
//<Set PDP context 0 
//<Set APN 
//<Activate PDP context,ret = 0
//<Select version 3.1.1 successfully
//<Start opening a MQTT client
//<Publish a message to server failure,ret = -1
//<Open a MQTT client successfully
//<state connection = 3

//<Start connect to MQTT server
//<Publish a message to server failure,ret = -1
//<Publish a message to server failure,ret = -1
//<Publish a message to server failure,ret = -1
//<Publish a message to server failure,ret = -1
//<Publish a message to server failure,ret = -1
//<Publish a message to server failure,ret = -1