It sounds like your Roku account isn't associated with the US. This can happen if you set up your account outside of the US and then moved to the US or for a couple of other reasons like using a VPN when you created the account. The only way to fix it is to create a new Roku account, factory reset the Roku device, and link it to the new account.
Roku Community Streaming Expert
Help others find this answer and click "Accept as Solution."
If you appreciate my answer, maybe give me a Kudo.
I am not a Roku employee.