A company runs a web application on AWS. The web application delivers static content from an Amazon S3 bucket that is behind an Amazon CloudFront distribution. The application serves dynamic content by using an Application Load Balancer (ALB) that distributes requests to a fleet of Amazon EC2 instances in Auto Scaling groups. The application uses a domain name setup in Amazon Route 53. Some users reported occasional issues when the users attempted to access the website during peak hours. An operations team found that the ALB sometimes returned HTTP 503 Service Unavailable errors. The company wants to display a custom error message page when these errors occur. The page should be displayed immediately for this error code. Which solution will meet these requirements with the LEAST operational overhead?