I cannot publish a service in port 8080

Traefik Traefik v2 (latest)
1

I cannot publish my service in port 8080 even I redirect dasboard to another port, Traefik automatically redirect URL http://localhost:8080 to http://localhost:8080/dasboard. I need to publish in port 8080 because infrastructure out of my control.
Everything works fine if I use another port to publish my service.
My docker-compose looks like:

version: "3.3"
services:
  traefik:
    image: "traefik:v2.8.1"
    command:
      - "--api.insecure=false"
      - "--providers.docker=true"
      - "--providers.docker.exposedbydefault=false"
      - "--entrypoints.traefik.address=:9090"
      - "--entrypoints.web.address=:80"
    ports:
      - "4000:9090"
      - "8080:80" # if I put another port works fine
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock:ro"
  salamandra:
    image: "salamandra"
    container_name: "salamandra"
    ports:
      - "5000:8080"
    labels:
      - "traefik.enable=true"
      - "traefik.http.routers.salamandra.rule=Host(`localhost`)"
      - "traefik.http.routers.salamandra.entrypoints=web"