Creating EC2 backup and getting "Access denied: Insufficient privileges..." error

Hello.

"PowerUserAccess" does not have permission to attach IAM roles, so service roles cannot be set when allocating resources with AWS Backup.
So, please set the following IAM policy for the IAM user and then try setting up AWS Backup.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Action": [
                "iam:PassRole"
            ],
            "Resource": [
                "*"
            ],
            "Effect": "Allow"
        }
    ]
}