If you can't add your card to Apple Pay (e.g. because you see an error), please make sure that:
• The card you're trying to add wasn't suspended or canceled.
• You're signed in to iCloud.
• You're using the latest version of the LINE app.
• You're using Apple Pay on a device that supports the service.
• You're adding a valid Visa LINE Pay prepaid card from the LINE app that you used to have it issued.
• You've removed any previously deleted Visa LINE Pay prepaid card from the Wallet app.
Note: JCB brand LINE Pay cards cannot be added.
If you want to use your card with your Apple Watch, you need to add your card to your watch from the LINE app first, and then add the card on your iPhone.
Let us know if we can make it better.