I am trying to execute the following code:
<?php
  function post_api($url, $postfields) {
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $postfields);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
    $result = curl_exec($ch);
    return $result;
  }
  $confirmations = 3;
  $callback = urlencode("https://website.ml/ipnbtc?id=2&email=email@gmail.com");
  $fee = "low";
  $rules = [
    array('address'=>'btc1', 'qouta'=> 95),
    array('address'=>'btc2', 'qouta'=> 5),
    array('address'=>'btc2', 'qouta'=> 0)
  ];
  $postfields = json_encode(array('type'=>"payment_distribution", 'payment_distribution'=> $rules ));
  $data = post_api("https://example.com/api/create/payment/smartcontract/". $callback . "?confirmations=" . $confirmations . "&fee_level=" . $fee, $postfields);
  echo $data;
  $respond = json_decode($data,true);
  $address = $respond["address"]; // Bitcoin address to receive payments
  $payment_code = $respond["payment_code"]; //Payment Code
  $invoice = $respond["invoice"]; // Invoice to view payments and transactions
?>
The error I get: {"error_code": 10, "message": "payment_list element incorrect keys", "details": ""}
How can i solve this error?