Laravel Coinpayment Issue "HMAC signature does not match"

Hello guys please i need help with this issue,i used coinpaymentHosted Lib ,i have set the creditiate correct but i am having this error message when i try to proccess transaction here is my code,

    $cps = new CoinPaymentHosted();
    $cps->Setup($gate->val2,$gate->val1);
    $callbackUrl = route('user.callback.coinpayment');

    $req = array(
        'amount' => (FLOAT) $Amountcharge,
        'currency1' => 'USD',
        'currency2' => $request->selectcrypto,
        'custom' => $transactionRecord->uuid,
        'ipn_url' => $callbackUrl,
        'cancel_url' => route('home'),
        );
    $result = $cps->CreateTransaction($req);
     dd($result);

i dont know if i am getting anything wrong or it coming from coinpayment, i have also install this package https://github.com/hexters/CoinPayment and set it according to usage but i still get the same error "HMAC signature does not match"

via Chebli Mohamed