REST Invoicing - recipient email not being sent

[BenGuri]

I'm trying to figure out why invoices are not being emailed to the recipients, upon invoking the 'send' API,  I'm answered with HTTP 200 (not HTTP 202 like described in the documentation), the response includes the content:

{

    "href": "https://www.paypal.com/invoice/p/#INV2-XXXX-XXXX-XXXX-XXXX",

    "rel": "payer-view",

    "method": "GET"

}

link is working, but the invoice is not emailed.

this is the the "create draft" request content:

{

  "detail": {

    "currency_code": "USD",

    "note": "Thank you for your business."

  },

  "invoicer":

  {

    "business_name":"myBusiness",

    "website":"https://www.myBusiness.com",

    "logo_url":"https://www.myBusiness.com/logos/myBusiness.png"

  },

  "primary_recipients": [

    {

      "billing_info": {

        "email_address": {RECIPIENT_EMAIL_ADDRESS}

      }

    }

  ],

  "items": [

    {

      "name": "Apple",

      "quantity": "1",

      "unit_of_measure":"AMOUNT",

      "unit_amount": {

        "currency_code": "USD",

        "value": "50.00"

      }

    }

  ]

}

the response is also shorter than what I should be receiving per the documentation:

{

    "rel": "self",

    "href": "https://api.paypal.com/v2/invoicing/invoices/INV2-XXXX-XXXX-XXXX-XXXX",

    "method": "GET"

}