When using the Stax Cost & Compliance module, you may receive an error message stating Access Denied to Detailed Billing Reports: We were unable to access the specified S3 bucket. This error means that Stax was unable to access the S3 bucket to retrieve your AWS accounts' billing reports.
The error means that Stax cannot use its IAM role to access the S3 bucket containing your billing data. You will need to identify what, in your account setup, is preventing Stax from accessing this information. See Cost and Compliance Module IAM Role Permissions for more information on the access Stax requires.