Post your question on the Echo Speaks thread
https://community.smartthings.com/t/release-echo-speaks-v3-actions/173073
I’m sure Anthony will be able to answer your question.
BTW, I enabled two factor Auth on my Amazon account just to prevent compromise on this kind of thing. Prevents bad actors from transporting my creds off of my heroku instance if they can even get them which I’m pretty sure heroku only has a login token. But better security is not a bad thing.