Most card failures come from the issuing bank, not us — a daily spending limit, a foreign-transaction block, or a fraud hold triggered by a new payee.
Try a smaller amount first, or call your card issuer and approve the transaction while you're on the line — many blocks clear instantly once you confirm it was you.
A bank transfer (ACH) avoids card blocks entirely and is free, though it takes 1–3 business days to clear before the transfer sends, versus instantly with a card.