Trying to initialize Stripe and create an event object in WordPress. Upon receipt of a webhook callback, Stripe fails to verify the response and returns the error, No signatures found matching the expected signature for payload.

$webhookSecret = defined('STRIPE_WEBHOOK_SECRET') ? STRIPE_WEBHOOK_SECRET : false;
try {
    $event = \Stripe\Webhook::constructEvent(
        $request->get_body(),
        $request->get_header('stripe-signature'),
        $webhookSecret
    );
    error_log("initialized stripe event object");
} catch (\Exception $e) {
    error_log("failed to initialize stripe event object");
    error_log($e->getMessage());
    return new WP_Error(403, 'error', __('message', $e->getMessage()));
}