The reasons are as follows:

1. Bank card restrictions: Consumers need to bind a credit card to use Apple's installment payment service. If the bank card is restricted, it cannot be used. Consumers need to check with their bank to resolve restrictions before trying to use the installment service.

2. Conflicts between Huabei and credit card payments: Some consumers encounter conflicts between Huabei and credit card payments when using Apple’s installment payment service. Huabei payment needs to be paid after the goods are confirmed to have been received, while credit card payment is made in real time and cannot be used at the same time. Consumers need to pay with Huabei and credit cards respectively, or convert Huabei into an installment payment method and then use Apple's installment payment service.

3. Insufficient balance: When using Apple's installment payment service to pay, you need to ensure that your bank card balance is sufficient, otherwise the payment will not be possible. Unable to pay due to insufficient balance, consumers contact their bank to increase their credit limit or Juxinbao limit, or choose to use other bank cards that support installment payment.

System failure: Apple's installment payment service is a system that runs on mobile phones, and system failure will also cause it to be unusable. When consumers encounter this situation, they try to restart their phones or update Apple's installment payment service.