This is usually a result of one of two issues:
1. Your account has been frozen due to a failed payment
If you have an existing paid account, with billing details already in our system, then your account may have been frozen as a result of a failed payment. In this case, you won't be able to make any more purchases or change your billing information until you contact us at email@example.com to 'fix' your account.
2. Can't input your postal code?
This tends to happen to American Express cards with Canadian billing details, as Stripe will provide a field for an American zip code instead of a Canadian postal code.
You may want to try using another card to register. Alternatively, you can contact us at firstname.lastname@example.org.
3. The payment was declined by your bank
Since Trint is a UK-based company, some card providers outside of the UK may not trust the source and will decline the transaction.
We recommend giving them a quick call to let them know that all Trint purchases are intentional. Alternatively, you could try another card.