Questions related to https communication between Fargate-based AWS ECS tasks

I distributed client tasks and apitasks inside private subnet to AWS ECS, but ACM is applied to the client task, so all requests from the client task become https communication, can't I do https communication based on ECS Fargate?

Additionally, when using the internal load balancer, I set the api service in the target group, but when I checked the ECS internal task, I checked that the server was operating normally, but the health check of the load balancer did not pass.

What are some ways to solve this overall problem?