If you choose “Hide My Email” when signing in with Apple, Apple automatically generates a relay email address.
This email address (with the @privaterelay.appleid.com domain) is not your actual address—it is issued by Apple.
● Emails from Zaiko will be sent to this relay address and then forwarded to your real email address.
● You cannot log in directly with this relay address.
● To access your account, you must always use “Sign in with Apple.”
● Entering your usual email address will not work.
👉 Apple Support: Manage apps that you use with “Sign in with Apple”
https://support.apple.com/ja-jp/HT210426