Hi There, 
 
	I'm trying to generate an invoice using the API. I have included the contents of my 'vars' parameter that is sent to the API.  The response i'm getting is just 
 
{"message":"The format requested is not supported by the server.","response":null}
	Is it something simple i'm missing here? Setting an option when I shouldn't be? The docs at http://source-docs.blesta.com/class-Invoices.html do not specify which options are optional on the invoice ( they do for lines of the invoice ) so I wasn't sure which ones were required.
 
	Does the invoice term need to match the service term some how?
 
	Update: I notice two of my lines below have a zero amount. I have tried without these and its the same result.
 
	Thanks in advance for any help!
 
<?php
$vars = array (
  'vars' => 
  array (
    'client_id' => 119,
    'currency' => 'GBP',
    'status' => 'active',
    'lines' => 
    array (
      0 => 
      array (
        'service_id' => 108,
        'description' => 'Minute Bundles',
        'amount' => 5,
        'tax' => true,
        'qty' => 1,
      ),
      1 => 
      array (
        'service_id' => 108,
        'description' => 'Included Top Up',
        'amount' => 0,
        'tax' => true,
        'qty' => 1,
      ),
      2 => 
      array (
        'service_id' => 108,
        'description' => 'Intergalactic Minutes Bundles',
        'amount' => 0,
        'tax' => true,
        'qty' => 1,
      ),
      3 => 
      array (
        'service_id' => 108,
        'description' => 'Handware Option',
        'amount' => 65,
        'tax' => true,
        'qty' => 1,
      ),
      4 => 
      array (
        'service_id' => 108,
        'description' => 'Plumbus Deluxe McSneeze',
        'amount' => 100,
        'tax' => true,
        'qty' => 1,
      ),
    ),
    'date_billed' => '2017-02-03 11:36:11',
    'due_date' => '2017-02-10 11:36:11',
    'term' => 1,
    'period' => 'month',
    'duration' => 'indefinitely',
  ),
);
?>