A suggestion: when registering in top-level domains (such as Europe) where the "c/o dynadot privacy" address option is invalid, the web interface should indicate that restriction before the order is submitted for processing.
Otherwise, it just shows oddball "rejected" flags for a while while waiting for the domain registration to complete - but doesn't really say what's wrong.
What I was seeing? Place an order, status would initially be "submitted" then "processing".
I would later see "rejected" as order status on the first domain listed on the order, something like https://www.dynadot.com/account/forum/f6-engineering-corner/uk-registry-problems-273.html
The problem would then disappear a wee bit later and the registration would finally appear as "completed".
Not sure why this happened, maybe it was just a temporary glitch that had nothing to do with the "c/o Dynadot Privacy" checkbox?
I'm not quite sure what you're referring to. Do you mean display an error message if an eu domain is being added to a shopping cart with the privacy box checked? Right now, it just doesn't add the privacy item to the cart, but doesn't show any rejected flags.