Access declined

Someone in your organization has blocked the root user in your account from making any changes to this particular resource. This is a wise decision as the root can be destructive in nature if used improperly. I suggest using a different IAM user or have the organization create one with appropriate permissions for you.

Please review this documentation on root user best practices: https://docs.aws.amazon.com/accounts/latest/reference/best-practices-root-user.html