I am trying to realize an https connection using a server certificate issued by Amazon Certificate Manager using an EC2 application load balancer. (I want to realize the composition of the image below)
Even if it is not a solution, I would appreciate it if you could tell me if there are other items to check.

Making websites HTTPS with AWS Part 1: ELB (+ ACM issuance certificate) → EC2Than

Operating conditions
  • http: // {public IP address}, http: // {public IP address}/health is accessible
  • 503 Service Temporarily Unavailable when accessing http: // {domain}, https: // {domain}
  • Looking at the load balancer with CloudWatch, it is counted by HTTPCode_ELB_503_Count (I can see that it is not a processing error on the EC2 side)
  • Even if I open the target in the EC2 target group and look at the monitor, Healthy Hosts etc. are displayed as "No data."
What went Application Load Balancer
  • From "Create Load Balancer" to "Application Load Balancer"
  • "Load balancer protocol" is HTTPS
  • Specify the certificate from "Select a certificate from ACM"
  • "Target group protocol" is HTTP
  • "Health check" is HTTP, specify/health
  • Obtaining a domain
  • Create a record and specify the alias created by ALB
  • Answer # 1

    I noticed that the zone specified by "Zone" in "EC2"->"Target Group"->"Targets" has not been added to the Availability Zone of the load balancer.
    As soon as I added this zone, I was able to access it safely through the health check.