I'm migrating our Health Cloud org over from using Candidate Patients to using Leads. 

To start, I'm using a test instance of a Lead object that I created using the "New" button the Leads list view.  When I select "Convert to Patient" from the list view and run through the 3 conversion wizard steps, I get a generic error: "Patient conversion failed.  Try again or contact your Salesforce admin for help" at the end.

To be clear, I haven't (yet) added any custom fields to the Leads object.  I've tried toggling "isMarkedForConversion" to no avail.  I'm just trying to get a minimally working example but can't seem to do so. 

Any thoughts?