Thanks for this tutorial. It works just fine. I'm however having a little challenge in the e-commerce app I'm building while trying to pass the total amount of the cart to Paystack "amount". Whenever I do so, the Paystack popup payment window does not open. Please what could be wrong? Here is my code chargeCard(BuildContext context) async { var cartItems = Provider.of<CartProvider>(context, listen: false); cartItems.fetchCartItems(); var charge = Charge() ..amount = (cartItems.totalAmount * 100) as int ..reference = _getReference() ..putCustomField('custom_id','846gey6w') //to pass extra parameters to be retrieved on the response from Paystack ..email = 'support@jumbocheap.com';