It looks like currently we can only search/create patients in the domain with EHR Source ID : 0b8a0111-e8e6-4c26-a91c-5069cbc6b1ca.
Are there more domains available in the sandbox for us to use? If not, is it possible for you to create a new test domain under the same root : fhir-ehr.sandboxcerner.com ?
The reason I'm asking this is that a lot of our clients are having multiple domains configured and we have some features that needs to be tested in multiple domains environment. It will be really helpful if the sandbox can mimic the multi domain environment so we can catch issues as early as possible.