Ted here from Shopify, thanks for reaching out to us. :-)
Are you using a debit or credit card for the payment? At this time, it's not possible to use a debit card for payments so you would need to be entering either a valid credit card from Mastercard, Visa, or American Express. As well the card would need to be able to accept recurring payments. We don't accept any other form of payment here at Shopify (such as Paypal etc as mentioned in this guide), so if you are using a valid credit card and it's still not working, I'd recommend reaching out to your bank for more info.
Please let me know how this goes! Feel free to reach out to our Support team any time as well. We're here 24/7 via Facebook, Twitter, chats, emails and phone. Just click 'talk to support’ for some more info.
Thanks a mill,
Are you using a debit card for the subscription? If so, the reason the charge went through for the domain was that it was a once-off charge. For a subscription plan, this is a recurring monthly charge with no set amount guaranteed. Because your monthly invoice may vary depending on transaction fees and app charges, some banks will not approve of our charge. A great breakdown of how we charge in full can be found here if you would like to take a look.
For this reason, we would always recommend using a credit card instead of a debit. This error may also occur if you are using a digital banking service, such as Revolut. If you are currently using a credit card from a bank though, we would recommend contacting your bank directly for more info.
If there is anything else I can help you with, please let me know, I'm happy to help!
Thanks a mill,