Apple is checking with your financial institution if the payment method is valid and receiving a negative, or no, response.
Use the document Add a payment method to your Apple Account - Apple Support to review your payment methods such as credit or debit cards.
On a mobile device:
1. Open the Settings app.
2. Tap your name.
3. Tap Media & Purchases, then tap View Account. You might be asked to sign in with your Apple ID.
4. Tap Manage Payments.
Check there are not any problems with your payment method. They will usually appear in red lettering. If there are, make sure the name and address are entered exactly as it appears on your financial institution bills and that the 3 digit CVV is correct. If everything appears correct, check with your financial institution about the status of your card.
It helps to make sure your payment method is from the same country to which your account is set.
The article: If your payment method is declined in the App Store or iTunes Store - Apple Support has some information about declined payment methods.
- Make sure your payment method is up to date or to try a different one ( If you need to change or update your Apple Account payment method - Apple Support ).
If you cannot see a reason for a problem, contact your financial institution first. Apple does not know why your card is not being verified. If your bank cannot help, contact Apple for assistance with this.
To contact Support, click on this link and choose a method —> https://getsupport.apple.com/?caller=cups&PGF=PGF63006&category_id=SC0060