Looks like the certificate expired.

This is in the above text - "Your client certificate is either not trusted or is invalid."

Or someone enabled check client certificate and didn't realize the implications.

Happy to share Kyle! Thanks for the great articles.

Stumbled upon a different InterSystems github project that in my testing and with a little configuration works as I expected (https://github.com/stefanc82/Cache-DynamicObject-Adapter). Any thoughts on which project might be the preferred path for future?

I didn't come across this project when I searched github for projects that mention %DynamicObject/%DynamicArray. I'll look into this project as well.