Payments can fail for all kinds of reasons, but here are a few things worth double-checking:
- Make sure you typed in the card details correctly (we’ve all done it)
- Check your card hasn’t expired (again, we’ve all been there)
- See if you entered the right billing address (especially if it’s different to your delivery address)
If this doesn't help, there may be the option to pay for your order with cash. You could also try contacting your bank to check your available balance or to see if the issue lies at their end.