Paypal rest - Credit card payment

Hi people;

I want to use paypal for my website, and for my payments I can use my credit card, and people can use credit card that could be not verified by paypal.

I'm setting my omnipay like this :

public function paiement()
    {
        $gateway = Omnipay::create('PayPal_Rest');

        $gateway->initialize(array(
            'clientId' => '********',
            'secret'   => '***********',
            'testMode' => false, // Or false when you are ready for live transactions
        ));

        $transaction = $gateway->authorize(array(
            'returnUrl'=> route('order'),
            'cancelUrl' => route('acceuil'),
            'amount'        => 12.99,
            'currency'      => 'EUR',
            'description'   => 'This is a test authorize transaction.',
            // 'card'          => $card,
        ));

        $response = $transaction->send();
        if ($response->isRedirect()) {
            // Yes it's a redirect.  Redirect the customer to this URL:
            $redirectUrl = $response->getRedirectUrl();
            return redirect($redirectUrl);
        }

    }

& my order is like this :

public function order(Guard $user)
    {
        $gateway = Omnipay::create('PayPal_Rest');

        $gateway->initialize(array(
            'clientId' => '******************',
            'secret'   => '*********************',
            'testMode' => false, // Or false when you are ready for live transactions
        ));

        $response = $gateway->completePurchase(array(
            'payerId'             => $_GET['PayerID'],
            'transactionReference' => $_GET['paymentId'],
        ));

        $finalResponse = $response->send();

    dd($finalResponse);

There is three isues :

• I'm on the test environment, No problem, I can do the purchase easily,
• I'm on the live, with a verified credit card, still no problem, I can do the payment.
• I'm on the live, without a verified credit card, but here, it's not working, I have this response in my dd();

RestResponse {#386 ▼
  #statusCode: 400
  #request: RestCompletePurchaseRequest {#388 ▶}
  #data: array:5 [▼
    "name" => "INSTRUMENT_DECLINED"
    "details" => []
    "message" => "The instrument presented  was either declined by the processor or bank, or it can't be used for this payment."
    "information_link" => "https://developer.paypal.com/docs/api/payments/#errors"
    "debug_id" => "638b4fd83c366"
  ]
}

Well, I don't understand why it's doing that.. Maybe it's because the website is not in https ?

If you have an idea about why i'm having this only because the credit card isn't verified by paypal, I would like to have my clients doing this even without a verified credit card or a guest account.

Well, thank you in advance