Hi @robevans, Please see the following documentation for more information: Configuring your environment for Sign in with Apple https://developer.apple.com/documentation/sign_in_with_apple/configuring_your_environment_for_sign_in_with_apple#3743946 For Sign in with Apple, the Private Email Relay Service is used to communicate to the private email addresses that users opt-in to providing your apps. As long as your email sources and domains are properly registered and their SPF and/or DKIM authentications are validated, there should be no message delivery issues. However, If there are configuration errors, you will receive a bounce back with a 550 5.1.1 Relay not allowed for or similar. Cheers, Paris X Pinkney | WWDR | DTS Engineer
Topic:
Privacy & Security
SubTopic:
General
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