Issue with PHP curl / json POST - php

Question

I am running into an issue trying to issue a POST to the chargify API log payments from within a form.
However, it appears that the POST is actually being sent as a GET for some reason as it's returning an error.
Can anyone offer any advice on what I may be doing wrong? Postman is working just fine sending a POST with the JSON as the body, but I can't get it to work from PHP.
(note: the <urlmaskedforprivacy> is obviously not in my actual code)
//find invoice id # using invoice number search form
$invoiceNumber = fRequest::get('invoicenumber');
$json = file_get_contents('https://<maskedforprivacy>.chargify.com/invoices.json?number=' . $invoiceNumber);
$returnedInvData = fJSON::decode($json);
$invoiceId = $returnedInvData[0]->invoice->id;
// grab form data as payment info to send to chargify
$paymentAmount = fRequest::Get('amount');
$memo = fRequest::Get('memo');
if ((isset($invoiceNumber,$paymentAmount,$memo))) {
$url = 'https://<maskedforprivacy>.chargify.com/subscriptions/' . $invoiceId . '/payments.json';
$params = array(
'payment' => array(
'amount' => $paymentAmount,
'memo' => (string)$memo
),
);
// encode as json
$content = FJSON::encode($params);
// send to chargify
$curl = curl_init($url);
curl_setopt($curl, CURLOPT_HEADER, false);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_HTTPHEADER,
array("Content-type: application/json"));
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, $content);
$json_response = curl_exec($curl);
$status = curl_getinfo($curl, CURLINFO_HTTP_CODE);
if ( $status != 201 ) {
die("Error: call to URL $url failed with status $status, response $json_response, curl_error " . curl_error($curl) . ", curl_errno " . curl_errno($curl));
}
curl_close($curl);
$response = json_decode($json_response, true);
}

Answer 1

I've used this one code, but it returns 401 error and asks for Basic auth. in json_response variable. May be you've missed it?
$paymentAmount = 10;
$memo = 'test';
$url = 'https://test.chargify.com/subscriptions/1/payments.json';
$params = array(
'payment' => array(
'amount' => $paymentAmount,
'memo' => (string)$memo
),
);
// encode as json
$content = json_encode($params);
// send to chargify
$curl = curl_init($url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_HTTPHEADER,
array("Content-type: application/json"));
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, $content);
$json_response = curl_exec($curl);
$status = curl_getinfo($curl, CURLINFO_HTTP_CODE);
if ( $status != 201 ) {
die("Error: call to URL $url failed with status $status, response $json_response, curl_error " . curl_error($curl) . ", curl_errno " . curl_errno($curl));
}
curl_close($curl);
$response = json_decode($json_response, true);