When purchasing AFL Mint digital collectibles, during the checkout process you have a choice of selecting Banxa or Moonpay as the on-ramp service provider. On-ramp refers to fiat exchanged into USDC Flow tokens, which is required for purchasing AFL Mint.
If you get this error, please attempt the alternative on-ramp provider, during the checkout process. If you have attempted purchasing with both Banxa and Moonpay, and continue to get this error, please contact your bank directly. This is not a fault with AFL Mint, Banxa or MoonPay, but rather is a policy of your bank.
You can attempt to use another credit card issued by a different bank, or a debit card. Alternatively, using ApplePay or GooglePay may allow the transaction to go through.