DNS resolution failed while trying to access GRPC container via BloomRPC

Traefik Traefik v2
,
1

I am using traefik v2.4 and I am experiencing a very weird problem with the my grpc service and I cant access it. Although, I can access the rest endpoints under the same container as the grpc endpoints.
I can also access other containers that use http and not h2c.

here is my docker-compose.yml

version: '3.7'

services:
  traefik:
    image: "traefik:v2.4"
    command:
      - --api.insecure=true
      - --api.debug=true
      - --providers.docker=true
      - --providers.docker.exposedbydefault=false
      - --providers.docker.watch
      - --entrypoints.web.address=:80
      - --entrypoints.websecure.address=:443
    ports:
      - "80:80"
      - "433:433"
      - "8080:8080"
    networks:
      - backend
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock:ro"

  # works
  whoami:
    image: "traefik/whoami"
    networks:
      - backend
    labels:
      - traefik.enable=true
      - traefik.http.routers.whoami.rule=Host(`whoami.localhost`)

  # works and redirect grpc-web requests to the below service
  envoy:
    image: envoyproxy/envoy:v1.16.0
    volumes:
      - ./envoy/configs/envoy-for-internal.yaml:/etc/envoy/envoy.yaml
    networks:
      - backend
    labels:
      - traefik.enable=true
      - traefik.http.routers.envoy.rule=Host(`grpc-web.localhost`)
      - traefik.http.services.envoy.loadbalancer.server.port=8080 # 8080 is the default envoy port

  brain:
    image: 'registry.gitlab.com/somaproject/e-boubouniera/go-backend/brain:latest-dev'
    volumes:
      - ../cmd/brain/config-internal.yml:/app/config.yml
      - ../cmd/brain/logs:/app/logs
    networks:
      - backend
    labels:
      - traefik.enable=true
      - "traefik.http.middlewares.serviceheaders.headers.accesscontrolalloworiginlist=*"

      # GRPC (I got DNS resolution failed by using BloomRPC grpc client)
      - "traefik.http.routers.grpc-brain.rule=Host(`grpc.localhost`)"
      - "traefik.http.services.grpc-brain.loadbalancer.server.scheme=h2c"
      - "traefik.http.services.grpc-brain.loadbalancer.server.port=9001"
      - "traefik.http.routers.grpc-brain.service=grpc-brain"
      - "traefik.http.routers.grpc-brain.middlewares=serviceheaders"

      # REST (works with postman)
      - "traefik.http.routers.rest-brain.rule=Host(`rest.localhost`)"
      - "traefik.http.services.rest-brain.loadbalancer.server.port=9002"
      - "traefik.http.routers.rest-brain.service=rest-brain"
      - "traefik.http.routers.rest-brain.middlewares=serviceheaders"

    stop_grace_period: 1m10s
    stop_signal: SIGINT

  devdb:
    image: postgres:12
    environment:
      POSTGRES_USER: "root"
      POSTGRES_PASSWORD: "example"
      POSTGRES_DB: "devdb"
    volumes:
      - ../.volumes/postgres:/var/lib/postgresql/data
      - ../database/init-db:/docker-entrypoint-initdb.d/
    ports:
      - "5434:5432"
    networks:
      - backend

networks:
  backend:
    driver: bridge

From traefik access logs, I can see that my calls never arrive to the traefik service

I cant understand why the grpc is not working. Any help please ?