With most OAuth systems a call to https://service/oauth/revoke?token={token} or along those lines should disconnect the user, I can't find anything like this in Sign in With Apple. Is this an option? It is needed for when a user removes their account 🙂

We have registered the full email addresses on the developer portal and they have green ticks next to them but are unable to send emails from them still, they just bounce back. We have also published a spf record for our domain, does anyone else have this problem? How can we fix it?