Why is my One4all Gift Card not adding to/working on Google Pay?

If you're attempting to add your card directly to your Google Wallet, this will fail when you try to verify with the CVV. You will need to download the One4all app, add your gift card to your account, and then from here you can add the card to Google Wallet.

If you're using a Google Pixel, your phone might try to autosave your card details when you add a physical One4all Gift Card to your One4all app. Click 'No thanks' on this screen, and use the 'Add to Google Wallet' button within the One4all app to add your card.

Make sure you have Google Wallet set as your default wallet app when you try to spend.

See 'How do I add a card to Google Wallet? for more details.