Can not use Apple ID balance to pay for Fitness Plus subscription

Hi everyone,

I just add money to my Apple ID Balance so my account balance is now enough to subscribe for 1 year of Apple fitness plus. However when i chose the annual plan, it showed that I don’t have sufficient funds. When I check again the payment method in my Apple ID, there are only 2 methods Paypal and Credit card. Are there anyway to fix it and use Apple ID balance as a payment method. Country/region is USA