How do I verify my Federated Account?

Thanks I've created Case ID 171644533800911 - I'll update here if I get an answer.

Hello.

I've seen this error occur when AWS imposes some kind of restriction on AWS account.
Therefore, I recommend that you contact AWS Support by opening a case under "Account and billing".
Inquiries under "Account and billing" can be made free of charge.
https://docs.aws.amazon.com/awssupport/latest/user/case-management.html