Invalid KML file using Smart Map Plugin
I like where you're going with this, but what you're trying to do isn't possible (yet).
As it currently stands, you need to use an Asset as the kmlFile parameter...
https://plugins.doublesecretagency.com/smart-map/kml-files/
It's on the roadmap to allow a string URL to be passed in directly.

UPDATE:
I've just added the ability to specify a KML by its absolute URL string. The new feature will be included in the next release of Smart Map. :)