Why are my emails to @privaterelay.appleid.com addresses failing with a 'HardBounce' error?

Emails sent to Apple's Private Relay addresses (ending in @privaterelay.appleid.com) may result in a 'HardBounce' if your sending domain has not been properly registered and verified with Apple.

Apple's service requires you to authorize any domains you wish to send emails from. If you attempt to send an email from an unverified domain, Apple will reject it. Our platform registers this rejection as a hard bounce and, to protect your sender reputation, automatically adds that specific email address to a suppression list. Once an address is on this list, no further emails will be sent to it.

To resolve this issue, please follow these steps:

1. Verify Your Sending Domain: Ensure that your domain is correctly registered and authorized within your Apple Developer account to be used with the Private Email Relay service. This is a mandatory first step.

2. New Emails Will Succeed: After your domain is successfully verified with Apple, any new emails sent to @privaterelay.appleid.com addresses will be delivered correctly.

3. Address Previously Bounced Emails: If you need to send emails to addresses that had previously bounced before you verified your domain, you will need to have them removed from the suppression list. Please contact our support team, confirming that your domain is now verified, and we can assist with clearing these specific addresses.