AWS Application Load Balancer + EC2 – 443 listener not working as expected

It sounds like you’re having some issues with your Application Load Balancer and its 443 listener on your Amazon EC2 instances. There are a few things you can check to troubleshoot this issue:

1. Make sure that the security group for your EC2 instances allows inbound traffic on port 443.
2. Make sure that the certificate you are using for the HTTPS listener is valid and properly installed on the EC2 instances.
3. Check the configuration of your Application Load Balancer and the settings for the 443 listener. Make sure that the listener is configured to forward traffic to the correct target group and that the target group is associated with the correct EC2 instances.
4. Check the network ACLs for the VPC in which your EC2 instances reside to ensure that traffic on port 443 is allowed.
5. If you are still experiencing issues, you can enable access logs for your Application Load Balancer and review the logs to see if there are any error messages that can help you identify the cause of the problem.

I hope this information helps! Let me know if you have any other questions or if there’s anything else I can do to help.