Trying to get Zoho to email an invoice

Trying to get Zoho to email an invoice

Hey Guys, I'm trying to get the zoho inventory api to work with our website, and we want to it auto create an invoice, then email that invoice once created.  I'm using this site as reference. 
  1. $invoiceEmail ='{
  2.    "send_from_org_email_id": false,
  3.     "to_mail_ids": [
  4.         "myemail@email.com"
  5.     ],
  6.     "cc_mail_ids": [
  7.         "myemail@email.com"
  8.     ],
  9.     "subject": "Invoice from Zillium Inc",
  10.     "body": "Dear Customer, Thanks for your business."
  11. }';
  12. $connectionStatus .= $zohoClient->emailInvoice($invoiceEmail);


  3. public function emailInvoice($params, $ignore = false)
    { 
         $invoiceID=7262;
         return $this->curlRequest("/invoices/{$invoiceID}/email", 'POST',
         ['JSONString' => $params]);
    }

When i attempt to run this test the only response I get back is

{"code":-1,"message":"Resource does not exist."}
All my other api calls work on this application, but I"m clearly doing something wrong.