I am integrating a 3d payment system with iyzico in my project. When I try with non-3d, I can get paid without any problems, but when I use 3d, I successfully send the threeDSHtmlContent value to the page. I get sms verification and after entering the code I get a csrf error when I have to go back to callBack and go to /paymentSuccess page. I couldn’t understand why. I integrated csrf protection into routes with middleware (locals). I would appreciate it if you could help.

`exports.postProcessPayment = (req, res, next) => {
const userId = req.user._id;
User.findById(userId)
    .then(user => {
        if (!user) {
            console.error('Kullanıcı bulunamadı.');
            return res.status(404).json({ error: 'Kullanıcı bulunamadı.' });
        }
        console.log('Kullanıcı bilgileri:', user);  
        const { name,cart,surname } = user;        
        const { cardNumber, expireMonth, expireYear, cvc, cardHolderName } = req.body;
        const cartItems = user.cart;
        user.cart = [];
        user.save(); 
        const totalPrice = calculateTotalPrice(cart);    
        const request = {
            locale: Iyzipay.LOCALE.TR,
            conversationId: '123456789', 
            price: totalPrice.toString(), 
            paidPrice: totalPrice.toString(), 
            currency: Iyzipay.CURRENCY.TRY,
            installment: '1',
            basketId: 'B67832',
            paymentChannel: Iyzipay.PAYMENT_CHANNEL.WEB,
            paymentGroup: Iyzipay.PAYMENT_GROUP.PRODUCT,
            callbackUrl: 'http://localhost:5050/paymentSuccess',
            paymentCard: {
                cardHolderName: cardHolderName,
                cardNumber: cardNumber,
                expireMonth: expireMonth,
                expireYear: expireYear,
                cvc: cvc,
                registerCard: '0'
            },
            buyer: {
                id: user.id,
                name: user.name,
                surname: user.surname,
                gsmNumber: `+90${user.phone}`, 
                email: user.email,
                identityNumber: '74300864791',
                registrationAddress: user.adress,
                address: user.address,
                city: 'İstanbul', 
                country: 'Turkey', 
                zipCode: '35000' 
            },
            shippingAddress: {
                contactName: name + ' ' + surname,
                city: 'İstanbul',
                country: 'Turkey',
                address: user.adress,
                zipCode: '35000'
            },
            billingAddress: {
                contactName: name + ' ' + surname,
                city: 'İstanbul',
                country: 'Turkey',
                address: user.adress,
                zipCode: '735000'
            },
            basketItems: cart.map(item => ({
                id: item.productId,
                name: item.name,
                category1: 'Product',
                category2: 'General',
                itemType: Iyzipay.BASKET_ITEM_TYPE.PHYSICAL,
                price: item.price.toString()
            })),
        };
        console.log('Request Bilgileri:', request);           
        iyzipay.threedsInitialize.create(request, function (err, result) {
            if (err) {                    
                console.error("Ödeme işleminde bir hata oluştu:", err);
                return res.status(500).json({ error: "Ödeme işlemi sırasında bir hata oluştu." });
            } else {                  
                console.log("Ödeme işlemi başarıyla tamamlandı:", result);
                if (result && result.threeDSHtmlContent) {                    
                    const threeDSHtmlContent = Buffer.from(result.threeDSHtmlContent,'base64').toString('utf-8');
                    res.send(threeDSHtmlContent); 
                } else {                     
                    const newOrder = new Order({
                        userId: userId,
                        products: cartItems.map(item => ({
                            productId: item.productId,
                            name: item.name,
                            quantity: item.quantity,
                            imageUrl: item.imageUrl,
                            price: item.price
                        })),
                        totalPrice: totalPrice,
                        paymentStatus: 'success',
                    });                     
                    newOrder.save()
                        .then(savedOrder => {                          
                            console.log('Sipariş başarıyla oluşturuldu:', savedOrder);                       
                            // res.redirect('/paymentSuccess');   
                        })
                        .catch(error => {                       
                            console.error("Sipariş oluşturma sırasında bir hata oluştu:", error);
                            res.status(500).json({ error: "Sipariş oluşturulurken bir hata oluştu." });
                        });
                }
            }
        });
    })
    .catch(error => {
        console.error("Kullanıcı bilgilerini alma sırasında bir hata oluştu:", error);
        res.status(500).json({ error: "Kullanıcı bilgilerini alırken bir hata oluştu." });
    });

};

routes.post('/processPayment', locals, shopController.postProcessPayment);
routes.get('/paymentSuccess', locals, shopController.getPaymentSuccess);`

/paymentSuccess needs to return to page.