Explanation help of "Path cannot be empty" exception

Can anyone explain what this exception means? Been banging my head against the wall trying to figure it out, and I assume I’m doing something dumb.

“Error while processing route: itinerary Path cannot be empty Error: Path cannot be empty”

What does Ember consider the “Path”? Something in the url, path to a template file, something else? I tried logging this path out within Ember and it looks to be an internal thing that gets auto set so I’m not sure why it wouldn’t be set.