Creating resources in a new sub-account of my organization is now giving SubscriptionRequiredException and OptInRequired errors. How do I get around this? Is this a bug in AWS?

I am programmatically creating accounts in my overall AWS organization then attempting to create resources (sns topics, sqs queues, lambdas, etc) for those accounts via terraform, using an IAM user's credentials that I also programmatically create for those accounts ahead of time.

The account and IAM creation works fine (I can see the account in the console), but when I attempt to run terraform apply I get either "SubscriptionRequiredException" or "OptInRequired The AWS Access Key Id needs a subscription for the service" errors.

I used to be able to do this just fine so it seems like either AWS changed something or they accidentally broke something in the last couple of years. I still have accounts I created 2-3 years ago using the exact same code that I can run terraform apply in just fine.

Here is another person complaining of the same issue (note: see the comment the OP made): https://www.reddit.com/r/aws/comments/v5iifl/losing_my_mind_while_trying_to_set_up/

I have checked that:

• I have consolidated billing enabled for my org
• One of my accounts is the management account
• My monthly bill does go to the management accounts credit card for all expenses in the org

Does anyone know why I am getting these errors even though my org appears to be set up correctly? Can I opt-in/subscribe to services programmatically from my programmatically-created accounts somehow?