Unexplained Order Cancellation -- How to Fix

If you have placed an order on Apple.com and it is getting inexplicably cancelled then you may find that the Apple Support staff may be unable to give you details as to why other than "verification failed" -- but fear not because this may be the fix for you. I was told by one support representative that the team that verifies the orders does not share what failed verification for privacy and security purposes (likely to prevent somebody who is attempt to impersonate you to obtain personal information about you and potentially succeed in making a fraudulent order). Mind you, this is just speculation as to "why", but this is how it seemed when trying to figure out why my order was being cancelled and I was not able to obtain specifics.

So before you panic, check the Apple ID associated with the order and ensure it has a valid shipping address associated with it. I have 2 Apple ID's (one for store and one for iCloud) and the iCloud one which I was using had NO associated shipping address because I had only previously used it to purchase digital goods.

You can do this at appleid.apple.com or in Settings app by clicking/tapping on your photo to manage your Apple ID and then choosing "Payment and Shipping".

Once I figured this out and added the shipping address, my order with Apple succeeded and was no longer automatically cancelled.