“Your account is unable to make this purchase on Xbox.com”

This can be a result of either your account being restricted due to your age, or Microsoft Account family settings.

It might also be an issue if you do not have a credit card or payment method associated with your account. When it comes to the Xbox 360 storefront (which includes the Xbox originals), they require that a purchase method be associated with the account even
for free titles. The Xbox One storefront does not have that same requirement.

If it's the latter, then you can add a payment method to your account at your
Microsoft Account profile page under Payments & Billing.

Hey there! Do you have a child or an adult account?

Hi Newt,

Thanks for letting us know that you've got the issue resolved and are working with your dad to temporarily change your restrictions to get the game. Since there is no further resolution and in an effort to minimize repetitive answers we will be locking
this thread, but if you have any further questions or concerns feel free to come back to the Xbox forums.

Thanks again and have a great day!

Ah. My dad has restrictions set, (however, they tend to have unintending side effects)

I’ll ask him to temporarily change it. Thanks!

Sorry Your account is unable to make this type of purchase on Xbox.com. Please complete this transaction from your Xbox.