Invalid API Response: - Got a non-object result, expected an object from create (undefined)

I am building an integration using the online developer portal 

I am getting the response  - Invalid API Response: - Got a non-object result, expected an object from create (undefined) when trying to create a record via our api .

In postman I get the following response from our api
{
    "id": "df6fd489-a498-4f48-b1f0-d330ede11597",
    "policy_group_id": null,
    "policy_group": {
        "id": null,
        "name": null
    },
    "name": "Dare Inc3",
    "policy_ref_number": "11211",
    "user_id": "xxxxxxxxxx-1564-44d0-835f-2447710a0b7b",
    "user": {
        "id": "xxxxxxxxx-1564-44d0-835f-2447710a0b7b",
        "sub": "xxxxxxxxx5e5b9006a14707d",
        "first_name": "Martin",
        "last_name": "",
        "avatar": "https://s.gravatar.com/avatar/cb135195defd73b472707171c06137ee?s=480&r=pg&d=https%3A%2F%2Fcdn.auth0.com%2Favatars%2Fma.png",
        "email": "martin@xxxxxxxx"
    },
    "policy_holder_id": "xxxxxxx-0ec7-4ed8-96cf-bc9cb20276e1",
    "policy_holder": {
        "id": "xxxxxxxxx-0ec7-4ed8-96cf-bc9cb20276e1",
        "name": "Martin xxxx",
        "email": null
    },
    "product": "some product",
    "gross_value": "239.89",
    "commission_split_template_id": null,
    "commission_template_id": null,
    "start_date": "2021-03-01T00:00:00.000000Z",
    "end_date": "2022-02-28T00:00:00.000000Z",
    "premium_value": 679.9,
    "payment_frequency_type": "month",
    "payment_frequency": 1,
    "status": "active",
    "created_at": "2021-03-02T11:49:23.000000Z",
    "updated_at": "2021-03-02T11:49:23.000000Z"
}

The code in the API request is 

const options = {
  url: `https://us-east-1-app-staging/api/v1/organisation/${bundle.inputData.organisation}/policies`,
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'X-TOKEN': bundle.authData.token
  },
  
  body: {
    'policy_holder_id': bundle.inputData.policy_holder_id,
    'name': bundle.inputData.name,
    'policy_ref_number': bundle.inputData.policy_ref_number,
    'premium_value': bundle.inputData.premium_value,
    'start_date': bundle.inputData.start_date,
    'end_date': bundle.inputData.end_date
  }
}

return z.request(options)
  .then((response) => {
    response.throwForStatus();
    const results = response.json;

    // You can do any parsing you need for results here before returning them

    return results ;
  });
 

Any ideas why the error is happening?

Thanks in advanced.