Thanks for stopping by the Apple Support Communities! From your post, I understand that you're trying to add a card to your wallet in Apple Pay, but are running into some trouble doing so. I'm happy to help!
Based on what you've described, I would recommend the following steps from Get help adding cards to Apple Pay - Apple Support :
Get help adding cards to Apple Pay
If you need help adding cards to Apple Pay, try the steps below.
Make sure that you can add a card
Learn which countries and regions support Apple Pay.
Check Apple Pay on the System Status page. If there's an issue, try again after it's resolved. If there isn't an issue, make sure that you're using:
- Your eligible device
- The latest version of iOS, watchOS, or macOS
- A supported card from a participating issuer
- An Apple ID signed in to iCloud*
*Apple Pay isn't available for children under 13.
Try to add a card
After each step, see if you can add your card to Apple Pay:
- Make sure that you're in a supported region.
- For your iPhone or iPad, go to Settings > General > Language & Region, then scroll to Region.
- For your Apple Watch, open the Watch app on your iPhone, go to the My Watch tab, tap General > Language & Region, and check the region format.
- For your MacBook Pro with Touch ID, go to System Preferences > Language & Region, and check the region.
- Restart your iPhone, iPad, Apple Watch, or Mac.
- Update to the latest version of iOS, watchOS, or macOS.
- Remove the card from Apple Pay, then add it again.
- For your iPhone or iPad, go to Settings > Wallet & Apple Pay, tap the card that you want to remove, and tap Remove Card. Then add the card back to Apple Pay.
- For your Apple Watch, open the Watch app on your iPhone, go to the My Watch tab, scroll down, and tap Wallet & Apple Pay. Tap the card and tap Remove. Then add the card back to Apple Pay.
- For your MacBook Pro with Touch ID, go to System Preferences > Wallet & Apple Pay, click the card that you want to remove, and click the minus (–) sign. Click Delete. Then add the card back to Apple Pay.
If you still can't add a card, contact your bank or card issuer for help.
In Italy, some UniCredit cards on the VPay and Maestro networks can be added to Wallet only using the UniCredit monhey app. Available in the App Store only in Italy.
Have a great day!