I have prime video NZ subscription. Signed in on my normal Amazon account and can log into prime video NZ on my Samsung TV app and via chrome.

But my fire tv and my android app seem to be associated with a Amazon USA only account.

I can't get these devices to recognize the Prime Video NZ subscription. It keeps on wanting me to subscribe again.

How to a link the NZ subscription to my phone and fire TV

PS the fire tv was purchased direct from the US several trays ago if that makes a difference.