Query your Application Load Balancer's domain name using your preferred method, such as dig or nslookup. Note the output from your query.

If Route 53 returns another record besides the Application Load Balancer's alias record, check the target groups behind the load balancer:

• If all the instances in a target group are unhealthy, Route 53 considers the record unhealthy. See
  Health Checks for Your Target Group for more information on how to perform health checks in the Elastic Load Balancing console, how to modify health check settings, and reason codes for health checks.
• If all the target groups behind a load balancer are empty (with no instances in them), Route 53 also considers the record unhealthy. See
  Register Targets with Your Target Group to add instances to your target group.

Troubleshooting example

This table shows an example Route 53 configuration for the domain example.com. The example client/resolver is located in the us-east-1 region. The example Application Load Balancer contains 2 target groups, TargetGroup1 and TargetGroup2, each with 2 instances. The example configuration uses latency-based routing. There is an alias record to an Application Load Balancer and a standard A record: