The error message 'AccessDenied' usually indicates that the AWS Backint agent does not have the necessary permissions to access the target S3 bucket. To resolve this error, an SAP basis administrator should assign an IAM role to the EC2 instance that is running the AWS Backint agent. Then, the administrator should attach a policy to the IAM role that grants the necessary permissions to access the target S3 bucket. This will allow the AWS Backint agent to access the S3 bucket and complete the backups successfully.