Hey, did you figure this out? I have a shopify store and also use authorize net and trying to do the set up is a nightmare. I'm still trying to find this well-known folder to verify my domain!
amdholistics
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
Post
Replies
Boosts
Views
Activity
what a nightmare this has been and Apple is completely unsupportive when you email them and just tell you to go to forums, utterly useless.