Traefik v1.7 docker always 404 page not found

I am setting up my VPS ($3.5 amazon free trier) with docker + traefik then I got a problem with traefik in swarm mode. Everything is running as well (traefik, https, docker). Although, I can access and see Traefik dashboard in srv1.webee.asia:8080, I always got 404 page not found when access the website in browser without 8080. The error log is "backend not found". I spent a day but am not resolved this problem. Anyone here for help!

There are my configs:

defaultEntryPoints = ["http", "https"]

[entryPoints]
  [entryPoints.http]
  address = ":80"
    [entryPoints.http.redirect]
    entryPoint = "https"

  [entryPoints.https]
  address = ":443"
  compress = true
    [entryPoints.https.tls]
    [entryPoints.https.forwardedHeaders]

  [entryPoints.traefik]
  address = ":8080"
    [entryPoints.traefik.auth]
      [entryPoints.traefik.auth.basic]
      users = ["admin:secret"]

[acme]
email = "contact@webee.asia"
storage = "acme.json"
entryPoint = "https"
onHostRule = true
  [acme.httpChallenge]
  entryPoint = "http"

[api]
entryPoint = "traefik"
dashboard = true
version: '3.6'

networks:
  traefik:
    name: traefik

configs:
  traefik.toml:
    external: true
    name: ${CONFIG_FILE:-traefik.toml}

services:
  traefik:
    image: traefik:1.7
    command:
      - --docker
      - --docker.watch
      - --docker.swarmMode=true
      - --docker.network=traefik
      - --docker.domain=${DOMAIN}
      - --docker.exposedbydefault=false
      - --configfile=/etc/traefik/traefik.toml
      - --loglevel=${LOG_LEVEL:-INFO}
    ports:
      - 80:80
      - 443:443
      - 8080:8080
    networks:
      - traefik
    configs:
      - source: traefik.toml
        target: /etc/traefik/traefik.toml
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - /opt/traefik/acme.json:/acme.json
      - /var/log/traefik:/var/log/traefik
    deploy:
      mode: global
      placement:
        constraints:
          - node.role == manager
      update_config:
        delay: 4s
        order: stop-first
      labels:
        - traefik.enable=true
        - traefik.port=8080
        - traefik.frontend.rule=Host:${DOMAIN}

Access dashboard directly via 8080:

Having this same problem - anyone know why all services would not be able to reach their backend, despite showing up correctly in the Dashboard (accessed via local IP:PORT).