There is currently a bug in the Xbox Store where players’ wishlists are empty
Microsoft cannot currently fulfill your wishes or no longer knows which ones you have.
There have apparently been problems with the wish list in the Microsoft Store via console and PC for a few days now. Previously saved products such as games are no longer there. The list is simply empty.
Since the list is completely empty, you may not receive a notification about games when they are on sale or you may be redirected to an empty list.
There is currently no point in filling the list again. If you save new games, they will disappear the next time you open them.
The issue may also be related to recent reports of players receiving emails for refunds that were processed months ago or codes that cannot be redeemed.
UPDATE: Wishlists have been restored.