Issue with app store downloading
There are several reasons why you can’t select none:


You have unpaid balance or a payment due.


If this is the case you have to pay your balance until you select none.


  You can't select None as your payment type until you pay your balance. To see which order you need to pay for, view your purchase history on a Mac or PC. 



You have an automatic renewing subscription.



  You might not be able to select None until you cancel the subscription. If the subscription has a free trial period, we use the payment method that you have on file to make sure that your service won't be interrupted after your free trial period is over. If you don't want to continue a subscription after the free trial, you can cancel the subscription to prevent any charges when the free trial ends.



If you are not in the country or region you created an Apple ID for.



  If you're creating an Apple ID for the first time, and you’re not physically located in the country or region at the time you create the Apple ID, you must enter a payment method. When this happens, you can't choose gift cards or store credit as your payment method. For example, if you’re in the United States, but you're creating an Apple ID with a billing address in China, you won't be able to choose None as payment method.



If you changed your country or region.



  When you change the country or region of an existing Apple ID, you must provide a payment method and update your billing options. When this happens, you can't choose gift cards or store credit as your payment method. If you want to remove your payment method after you change the country or region, you can change your payment information to None.



If you’re part of family sharing



  When you set up Family Sharing, the family organizer must provide a valid payment method. This payment method will be used for all purchases initiated by family members and can only be changed by the family organizer.


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