Secure MQTT communication using SIM808 GSM/GPRS modem



I am trying secure MQTT with AWS using SIM808 module.
Non secure TCP communication works fine.

Bit with AWS it permits only Secure connection.
I tried with creating a certificate using AT+FSCREATE, AT_FSWRITE commands

Setting SSL certificate with SSLSETCERT

AT+SSLSETCERT requires a password.

The certificate AmazonRootCA1.pem is downloaded from Amazon cloud. There is no password associated with that.

Only additional files downloaded are c906a347b6-private.pem.key and c906a347b6-public.pem.key.

But the length is more than 32 bytes.

I tried make password field NULL like

AT+SSLSETCERT=“C:\User\CA.pem”,"" reports +CME ERROR: Param value range beyond ERROR

How can I solve the situation??

Any references or workarounds might be helpful.

Thanks In advance