"Please enter subject" error when creating incident

I'm new to using Service Desk APIs and have managed to get my authentication working and can successfully call getIncidents. However, when trying to call the createIncident API with a simple JSON object:

{
    "incident": {
        "name":"Incident Name",
        "description":"description",
        "assignee": {
            "email":"john.doe@email.com"
        },
        "requester": {
            "email":"john.doe@email.com"
        },
        "priority":"High"
    }
}
I receive a 422 Unprocessable Content error with the following body:
{
    "name": [
        "^Please enter subject"
    ]
}

I'm appending the following headers in the request:

Acceptapplication/vnd.samanage.v2.1+json
Content-Typeapplication/json
X-Samanage-AuthorizationBearer ***********************************************

Thanks for any help.