Invoking "ScheduleListResources" I get "unknown" status even after increasing timeout.

I'm trying to automate resource discovery using SDK. When I invoke verb "ScheduleListResources" and then check on its status I always get 'Unknown'. I tried waiting several minutes but it's the same result. I did a sanity check and was able to pull list of resources using web console.
I used this code as a reference: github.com/.../ImportListResources.ps.

Am I missing anything?