AWS: Even though the Billing Policy attached, the IAM user account was not granted the permission
An IAM user account could not access the Billing and Cost Management home page.
Even though the Billing Policy was attached to the IAM account.
Finally, solved it with the [1].
The Policy did not work because, in default, "IAM user/role access to billing information" was deactivated.
How-to
1.
Navigation pane > Account
2.
Scroll Down to "IAM user and role access to Billing information". Then, activate it.
References
[1] How do I troubleshoot IAM permission issues for the Billing and Cost Management console?
https://repost.aws/knowledge-center/iam-billing-access
Overview of managing access permissions
https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/control-access-billing.html
Migrating access control for AWS Billing
https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/migrate-granularaccess-whatis.html
Update
Even though the Billing Policy was attached to the IAM account.
Finally, solved it with the [1].
The Policy did not work because, in default, "IAM user/role access to billing information" was deactivated.
How-to
1.
Navigation pane > Account
2.
Scroll Down to "IAM user and role access to Billing information". Then, activate it.
References
[1] How do I troubleshoot IAM permission issues for the Billing and Cost Management console?
https://repost.aws/knowledge-center/iam-billing-access
Overview of managing access permissions
https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/control-access-billing.html
Migrating access control for AWS Billing
https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/migrate-granularaccess-whatis.html
Update