Help with Paypal Live Transactions

I am using a web video script that has Paypal integrated.
Upon attempting a live transaction to test, the process proceeds to Paypal, shows the transaction amount and returns to the web site suceessfully, however no amount is added to the website and no amount is deducted from the paypal user account.

After checking the paypal developer dashboard Event Logs, I see that Event showing “HTTP Status 201 OK”.

I’ve contacted Paypal support (and the website script developer). Paypal said this:

“Live transactions issue: If the transaction seems to complete successfully but no funds are transferred, it might be an issue with your website’s integration with PayPal. You may want to verify that your website properly handles the IPN (Instant Payment Notification) or other callback mechanisms that PayPal uses to inform your website of a successful payment. Check your website’s logs and any IPN listener script to see if there are any errors or issues that need to be resolved”

I see nothing in the web script Error Log and cannot get prompt assistance through the script developer.
I don’t know how/where to “verify that your website properly handles the IPN (Instant Payment Notification) or other callback mechanisms that PayPal uses to inform your website of a successful payment…any IPN listener script”.

In the script’s files I see the paypal_config.php file, that looks like this:

$url = "https://api-m.sandbox.paypal.com";
if ($pt->config->paypal_mode == 'live') {
    $url = "https://api-m.paypal.com";
}

$pt->paypal_access_token = null;
$ch = curl_init();

curl_setopt($ch, CURLOPT_URL, $url . '/v1/oauth2/token');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, "grant_type=client_credentials");
curl_setopt($ch, CURLOPT_USERPWD, $pt->config->paypal_id . ':' . $pt->config->paypal_secret);

$headers = array();
$headers[] = 'Content-Type: application/x-www-form-urlencoded';
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

$result = curl_exec($ch);
curl_close($ch);
$result = json_decode($result);
if (!empty($result->access_token)) {
  $pt->paypal_access_token = $result->access_token;
}

Just thought I’d see if anyone here has integrated Paypal and could possibly direct me to where might be other files typical in a paypal integration. Or where else I might look for a solution…
Ultimately, I’m trying to remedy the issue that the developer is unavailable to do so.

I look forward to any clues you might provide.

What’s $pt->config->paypal_mode set to? (If your URL is still pointing at the sandbox, no transfer will actually happen, because… it’s the sandbox).

It is set correctly.

Upon processing a Live Transaction I see this in ‘Webserver SSL transfer log’:
...."GET /aj/wallet/get_paid?status=success&amount=1.00&token=6H326569M0899450A&PayerID=ZVLJWCX8ST4TS HTTP/2.0" 302 - "https://www.paypal.com/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.0.0.0 Safari/537.36"

Does this provide any clues as to why no amount is added to the website and no amount is deducted from the paypal user account?

Any suggestion is welcomed.