Why isn't my PayMongo webhook capturing failed test payments?

I'm working on a project integrating PayMongo as our payment gateway, and I've encountered an issue where the webhook doesn't capture failed payment responses.

When I select the 'Fail Test Payment' option, the system doesn't trigger the webhook; instead, it redirects back to the payment page for another selection, without stopping the payment process.

Below is the webhook code I'm using:

PHPCopied
ini_set('display_errors', 1);
error_reporting(E_ALL);

function logWithTimestamp($message) {
    $timestamp = date('Y-m-d H:i:s');
    if (is_array($message) || is_object($message)) {
        $message = print_r($message, true); // Convert array/object to string
    }
    file_put_contents("webhook_log.txt", "[$timestamp] $message" . PHP_EOL, FILE_APPEND);
}

$payload = file_get_contents("php://input");

if (!$payload) {
    logWithTimestamp("No payload received.");
    http_response_code(400);
    echo json_encode(["message" => "No payload received"]);
    exit;
}

data = json_decode($payload, true);

if (json_last_error() !== JSON_ERROR_NONE) {
    logWithTimestamp("JSON Decode Error: " . json_last_error_msg());
    http_response_code(200);
    echo json_encode(["message" => "Invalid JSON format"]);
    exit;
}

function searchArray($array, $keys) {
    $result = [];
    
    $recursiveSearch = function ($array, $key, &$found) use (&$recursiveSearch) {
        if (is_array($array)) {
            foreach ($array as $k => $v) {
                if ($k === $key) {
                    $found[] = $v;
                } elseif (is_array($v)) {
                    $recursiveSearch($v, $key, $found);
                }
            }
        }
    };

    foreach ($keys as $key) {
        $found = [];
        $recursiveSearch($array, $key, $found);
        $result[$key] = count($found) === 1 ? $found[0] : $found;
    }

    return $result;
}

$jsonResponse = $data;

$keysToFind = ['id', 'status', 'source'];

$values = searchArray($jsonResponse, $keysToFind);

$paymentId = $values['id'] ?? null;  // PayMongo payment ID is usually the second 'id' found
$paymentSource = $values['source'] ?? null;
$status = $values['status'] ?? null;

$test = [$paymentId, $paymentSource, $status];

logWithTimestamp($test);

http_response_code(200);
exit

I have enabled error reporting and detailed logging, but the webhook still doesn't seem to catch the failed payment. Has anyone encountered this issue or have insights on why the failed payment response isn't being received by the webhook?