Calling Service A from B is giving connecton refused using ECS CLI with docker compose. What might be the reason?

Question

I have setup an ECS Cluster and I'm using ECS CLI to create services/tasks from my existing docker-compose file. This is how my compose file looks like:

version: "3"
services:
  service-a:
    image: 537403345265.dkr.ecr.us-west-1.amazonaws.com/service-a:latest
    environment:
      - SPRING_PROFILES_ACTIVE=dev
    ports:
      - "8100:8100"
  service-b:
    image: 537403345265.dkr.ecr.us-west-1.amazonaws.com/service-b:latest
    environment:
      - SPRING_PROFILES_ACTIVE=dev
      - SERVICE_A_BASE=service-a:8100
    ports:
      - "8101:8101"
    depends_on:
      - service-a

and my ecs-params.yml:

version: 1
task_definition:
  task_execution_role: ecsTaskExecutionRole
  ecs_network_mode: awsvpc
  os_family: Linux
  task_size:
    mem_limit: 2GB
    cpu_limit: 256
run_params:
  network_configuration:
    awsvpc_configuration:
      subnets:
        - "subnet-xx"
        - "subnet-xy"
      security_groups:
        - "sg-xz"
      assign_public_ip: ENABLED

where I'm using SERVICE_A_BASEas the base URL for calling service A from Service B. The same compose file works fine in my local but it is not working inside my ECS Cluster. I have set inbound rules to allow ports 8100 and 8101 in my security group.

What might be wrong or Is there an another way of doing this?