Pin payments have a limit to the amount that can be processed through them per transaction and it may vary from account to account.
The reason you get this error could be because you are trying to process a payment above the maximum amount that can be processed through your Pin payments account.
If you've found that a transaction for a lower amount goes through without issues, it is most likely due to Pin payments limit. You could get in touch with the gateway provider in case you would like to increase the limit.
Another instance you see this error is when customers use an AMEX card to make the payment. This is because currently, Amex is an early-access program by way of opt-in only. To get this enabled for your account, you can contact Pin Payments.