How do I enable Apple Wallet on my Watch? Having issues...

I have an iPhone and the latest OS. I have Apple Wallet and am set up with my bank card for use with ApplePay. But, I can't seem to enable it on my watch.

Is this because it's already set up? When I go in to set it up it shows the card but it asks me to add that card. When I do go in to add it, after entering the correct pin for the card, the message I get is that it's an invalid card.

I'm not sure what's going on.

Some more information: I'm in Austria and the bank card is via Raiffeisen. When I originally added the card to my wallet I had to use a Raiffeisen app to add it. Maybe this is the issue?