Reported that Apple Watch wallet app will not sync after updating to watchOS 8.4

On iPhone and Apple Watch, you can use Apple Pay , a contactless payment service, by registering your credit card in the wallet app. However, after updating to the latest version of iOS, iOS 15.3, and the latest version of watchOS, watchOS 8.4, there is a problem with syncing the wallet app, which makes Apple Pay unavailable on the Apple Watch. Became clear.

Apple Watch Wallet sync issues found following watchOS 8.4, iOS 15.3 update | AppleInsider
https://appleinsider.com/articles/22/01/29/apple-watch-wallet-sync-issues-found-following-watchos-84-ios-153-update

On January 26, 2022, Apple released the latest versions of its own operating systems, including iOS 15.3 and watchOS 8.4. This update was basically a bug fix, but it has been reported that some users are having trouble syncing the iPhone wallet app with the Apple Watch wallet app.

Distribution of 'iOS 15.3' has started, and a vulnerability that leaks Google account information from Safari has been fixed --GIGAZINE

The bug has been reported on the Reddit and Apple official support communities, saying that 'Apple Pay is no longer available on the Apple Watch due to the iPhone and Apple Watch wallet apps being out of sync.' According to Apple Insider, an Apple-related media, the bug only occurs when the iPhone and Apple Watch wallet apps are synced.

iPhone and apple watch don't sync ticket on wallet: Apple Watch
https://www.reddit.com/r/AppleWatch/comments/seo2rz/iphone_and_apple_watch_dont_sync_ticket_on_wallet/

Problems with apple wallet in apple watch --Apple Community
https://discussions.apple.com/thread/253615580

Also, if you delete the credit card that has a synchronization problem from the wallet app of Apple Watch, the same credit card will be deleted from the wallet app on the iPhone side, but you can add a new credit card etc. with the wallet app on the iPhone side. However, the card will not be added to the Apple Watch wallet app. In other words, although the synchronization of 'Apple Watch wallet app-> iPhone wallet app' is working normally, the synchronization of 'iPhone wallet app-> Apple Watch wallet app' is not working.

However, Apple Insider, an Apple-related media outlet, points out that 'the number of users reporting this bug is relatively small, so the problem may not be so widespread.' In addition, one user reported that 'I use Apple Pay on my Apple Watch every day, so I called Apple's official support three times, but it did not help,' Apple has already raised the problem. It seems that you know it, but you don't seem to have a solution.