Hi tl99live,
Welcome to the Samsung Developer forum!
The country /region in your Samsung account profile determines the country/region in your Seller Portal profile.
If you have not completed your Seller Portal account registration, update the country/region in your Samsung account profile and then complete your Seller Portal account registration.
If you have completed your Seller Portal account registration, you will need to delete your Seller Portal account, update the country/region in your Samsung account profile, then re-register for a Seller Portal account.
Please see this post https://forum.developer.samsung.com/t/i-cant-change-the-country-when-registering/39424/2 for more detailed information.