traefik v2 dashboard basic auth not working behind AWS elb

I have my traefik v2 setup and when i try to access the dashboard which is behind AWS elb, the basic auth doe not work. But the same configu works when i hit traefik directly

here is what my config looks like

version: '3.5'

services:
  traefik:
    image: traefik:v2.2
    container_name: traefik
    restart: always
    command:
      - "--api.insecure=true"
      - "--providers.docker=true"
    networks:
      - traefik_network
    ports:
      - "80:80"
      - "8080:8080"
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    labels:
       - "traefik.enable=true"
       - "traefik.docker.network=traefik_network"       
       - "traefik.http.services.traefik.loadbalancer.server.port=8080"
       - "traefik.http.routers.traefik.rule=Host(`traefik.local.host`)"
       - "traefik.http.routers.traefik.middlewares=traefik"
       - "traefik.http.middlewares.traefik.basicauth.users=admin_user:$$apr1$$1smybfkx$$qsMzjTHGHyEn12LKmbNMC."
       - "traefik.http.middlewares.traefik.basicauth.removeheader=true"

networks:
  traefik_network:
     name: traefik_network

What do i need to do to have basic auth work for the traefik v2 dashboard when am behind AWS elb???

Did i post this in the wrong place? just want to make sure it gets the right exposure and in relevant space