Integrating Paypal Rest API SDK to laravel 5.2

I also faced this problem - in my case it I actually sent falsy data to paypal.

In a first step try to catch the Exception and get the actualy errormessage

// For testing purpose use the general exception (failed to catch with paypal for me)
catch (Exception $ex) {
  if (\Config::get('app.debug')) {
    echo "Exception: " . $ex->getMessage() . PHP_EOL;
    $err_data = json_decode($ex->getData(), true);
    exit;
  } else {
    die('Some error occur, sorry for inconvenient');
  }
}

The resulting message should give you enough information to solve what you got wrong.

Below i paste you my code which is working for me using paypal REST api. You will need 3 routes

• /payments/create (create payment)
• /payments/success (validate payment was successful & redirect from paypal)
• /payments/cancel (handle cancellation of paypal)

You will also need to add you paypal config and initialize it in your controller. If you do not have a paypal config file yet you can set the client id and secret directly in the function. The settings should be like this

 'settings' => array(
    /**
     * Available option 'sandbox' or 'live'
     */
    'mode' => 'sandbox',

    /**
     * Specify the max request time in seconds
     */
    'http.ConnectionTimeOut' => 30,

    /**
     * Whether want to log to a file
     */
    'log.LogEnabled' => true,

    /**
     * Specify the file that want to write on
     */
    'log.FileName' => storage_path() . '/logs/paypal.log',

    /**
     * Available option 'FINE', 'INFO', 'WARN' or 'ERROR'
     *
     * Logging is most verbose in the 'FINE' level and decreases as you
     * proceed towards ERROR
     */
    'log.LogLevel' => 'FINE'
)

Constructor of Controller

    $paypal_conf = config('paypal');
    $this->_api_context = new ApiContext(new OAuthTokenCredential($paypal_conf['client_id'], $paypal_conf['secret']));
    $this->_api_context->setConfig($paypal_conf['settings']);

Create Route

    // create a payment
    public function create(Request $request)
    {
        $payer = new Payer();
        $payer->setPaymentMethod('paypal');

        $price = '10.00'; // 10 € for example

        if($price == 0) { // ensure a price above 0
            return Redirect::to('/');
        }

        // Set Item
        $item_1 = new Item();
        $item_1->setName('My Item')
            ->setCurrency('EUR')
            ->setQuantity(1)
            ->setPrice($price);

        // add item to list
        $item_list = new ItemList();
        $item_list->setItems(array($item_1));

        $amount = new Amount();
        $amount->setCurrency('EUR')
            ->setTotal($price); // price of all items together

        $transaction = new Transaction();
        $transaction->setAmount($amount)
            ->setItemList($item_list)
            ->setDescription('Fitondo Fitnessplan');

        $redirect_urls = new RedirectUrls();
        $redirect_urls->setReturnUrl(URL::to('/payment/status'))
            ->setCancelUrl(URL::to('/payments/cancel'));

        $payment = new Payment();
        $payment->setIntent('Sale')
            ->setPayer($payer)
            ->setRedirectUrls($redirect_urls)
            ->setTransactions(array($transaction));

        try {
            $payment->create($this->_api_context);
        } catch (\PayPal\Exception\PayPalConnectionException $ex) {
            if (config('app.debug')) {
                echo "Exception: " . $ex->getMessage() . PHP_EOL;
                $err_data = json_decode($ex->getData(), true);
                exit;
            } else {
                die('Error.');
            }
        }

        foreach($payment->getLinks() as $link) {
            if($link->getRel() == 'approval_url') {
                $redirect_url = $link->getHref();
                break;
            }
        }

        /* here you could already add a database entry that a person started buying stuff (not finished of course) */

        if(isset($redirect_url)) {
            // redirect to paypal
            return Redirect::away($redirect_url);
        }

        die('Error.');
    }

Success Route

public function get(Request $request)
{
    // Get the payment ID before session clear
    $payment_id = $request->paymentId;

    if (empty($request->PayerID) || empty($request->token)) {
       die('error');
    }

    $payment = Payment::get($payment_id, $this->_api_context);

    // PaymentExecution object includes information necessary 
    // to execute a PayPal account payment. 
    // The payer_id is added to the request query parameters
    // when the user is redirected from paypal back to your site
    $execution = new PaymentExecution();
    $execution->setPayerId($request->PayerID);

    //Execute the payment
    $result = $payment->execute($execution, $this->_api_context);

    if ($result->getState() == 'approved') { // payment made

        /* here you should update your db that the payment was succesful */

        return Redirect::to('/this-is-what-you-bought')
            ->with(['success' => 'Payment success']);
    }

    return Redirect::to('/')
        ->with(['error' => 'Payment failed']);
}

I hope I got everything - I had to clean up my code a little to simplify it.