@Product I had a "Send SMS" work action return an "Unsuccessful" response.
WA-12: Send SMS completed with Unsuccessful at 11:30:15 AM
Execution ID: 75ec1a88-b6f1-497e-bc9b-07035e394c3b
However, on the designer it shows "Success" and "Failure" as the two statuses.

I had a wrk action connected to the "Failure" branch but it didn't trigger that action on the "Unsuccessful"