In some cases RemNote will not be able to bill your credit card, preventing you from buying the pro subscription.
Please take these steps to fix this issue:
Please confirm with your bank that your credit card supports foreign/online payment, or
Try using another credit card. See more about payment methods here.
If you don’t have another credit card, you can also consider using a prepaid debit card. You can likely find such cards in a local convenience store.
If none of these work, please contact support.