In most cases pledging issues may be due to a problem with the card used.
We recommend the following troubleshooting steps:
Double check to make sure that the card number, expiry date, security code and billing postcode have all been entered correctly.
Contact your bank to make sure there are no holds on your card and to also make sure that.
No additional authorisation is required of you
Your card is authorised for foreign transactions if you're pledging from outside of the UK
If you're using a pre-paid card or debit card, that you have enough funds available
If you're having trouble, try using a different card for the payment.
If the issue you are having is related to the address you are inputting please see this guide.