A common issue for a first transfer to fail to a debit card is that you haven’t yet called your bank and enabled third-party transfers. This could be a reason why your card is “unsupported” at the moment. Just call your bank, have them enable third-party transfers and then wait 24 hours to try again.
Unfortunately, not all US banks support our Now transfers to debit cards, but we’re working hard to get more banks on board.
AMEX and Discover cards are not supported by our debit card network. Prepaid debit cards and small banks, like credit unions, occasionally do not work with our Now transfer network as well.
Unfortunately, we are not able to see the exact reason the card is unsupported within the Visa/Mastercard system. You may contact the 1-800 number on the back of the debit card for a further explanation or to have third-party transfers enabled for your card. Alternatively, you can always add another card to try a Now transfer.