I am using SIM808 module. It's working fine with normal MQTT over TCP. But it's not working while implementing secured MQTT. I am sending this command (AT+SSLSETROOT="C:\USER\HENRY_SSL.CRT")to set the root certificate (referred this document"SIM800 Series_MQTT_Application Note_V1.03"), the response I'm getting from gsm is "+CME ERROR: unknown". If I'm using this command (AT+SMSSL=1), same error I'm getting. I checked with HTTP commands it's working fine, But AT+HTTPSSL=1 command not working. The sim808 not responding SSL related commands.
But as per the simcom website sim808 supports SSL. Do I need to upgrade any firmware or is there any workaround to solve this issue? Any suggestions or guidance will be very helpful. Thanks in advance!