Please review the failed transaction in the app for more accurate information about your contactless payment. In general, contactless payments can be declined for the following reasons:
If you've never made an in-store payment with your card, you need to make a payment using chip and PIN code in order to activate the contactless feature.
You can check if contactless is disabled for a specific card by choosing 'PIN & Security' option for the relevant card.
You can reset it by either going to 'PIN & Security' option under the relevant card -> Reset contactless limit, or make a chip & PIN transaction with your card. After that, you'll be able to continue using contactless until the next reset is needed.
Please double-check that the terminal you are paying at supports contactless; payments can also get declined due to connection issue.
If your physical card has been damaged or has worn out, you can order a replacement card. The estimated delivery date will be provided at checkout.