payment method is not authorised

A “payment declined” or “card declined" message means that the issuer of the credit or debit card you have on file in your iTunes account rejected a charge or account confirmation. It is not an Apple problem; Apple is just passing through the message from your issuer. There are a number of reasons the charge or verification might be declined:

• Insufficient balance or account in arrears
• Account suspended for suspected fraud (not necessarily by you)
• Error in card number
• Wrong expiration date
• Wrong security (CVV) code
• Address in your iTunes account does not match exactly the billing address for the card
• The card was not issued in the country of the iTunes store
• You are connected through a VPN provider that does not terminate in the country of the iTunes store you are connected to.

Here is additional information from Apple→If your payment method is declined in the App Store or iTunes Store - Apple Support

Hi sandhya211,

Thanks for using Apple Support Communities. You've mentioned that you're unable to use the payment method that's associated with your account. Have you tried changing the payment method or verifying that it can be used in your region? Take a look at the following link and let us know if this helps.

If your payment method is declined in the App Store or iTunes Store

Take care.