Cannot POST a new Patient using Epic on FHIR sandbox

[Bogdan Moskalevsky]

I’m having trouble creating a new Patient in Epic’s sandbox. I use one of the sandbox’s test patients but change some fields e.g. birthDate. No matter what I do I get a 400 Bad Request error with some confusing error messages.

1. Register an app with Epic on FHIR.
2. Authenticate for server-to-server and GET the first sandbox patient (Camila Lopez).
3. Use that patient JSON to POST a new patient: change the birthDate.
   You get a 400 error and "An element value is invalid." "/f:address/f:use" message.
   

I tried changing the identifiers and get the same error.

Did somebody encounter the same problem? Is it even possible to create a new patient in the sandbox?