What is a possible reason for this issue?

A web application runs on Amazon EC2 instances behind an Application Load Balancer (ALB). The instances run in an Auto Scaling group across multiple Availability Zones. A SysOps administrator notices that some of these EC2 instances show up as healthy in the Auto Scaling group but show up as unhealthy in the ALB target group.

What is a possible reason for this issue?
A . Security groups are not allowing traffic between the ALB and the failing EC2 instances.
B . The Auto Scaling group health check is configured for EC2 status checks.
C . The EC2 instances are failing to launch and failing EC2 status checks.
D . The target group health check is configured with an incorrect port or path.

View Answer

Answer: A