Issue
There is no wishlist in your app, thus your app users cannot add favorite items to wishlist for later purchase.
Cause
This issue may happen because you disable wishlist on your website.
Solution
To turn on wishlist on your site, please do the following:
Step 1: Log in to Magento Admin, then go to Stores > Configuration > Customers > Wish List > General Options. Make sure that Enabled is set to YES.
Step 2: Clear cache by going to System > Cache Management > Flush Magento Cache.
Step 3: Open your app and wishlist is now available.