My own sample rootCA is failing on handshaking with aws

HI @manish_arm
Thank you for your query.

It seems that this issue is not related to the original post, so it merits a new topic.
May I know what is the Mbed TLS version you are using?

Usually, RSA verification fails when the key that was used to sin the message is not the keypair of hte public key that is used to verify the message.