我在社区论坛上发布了一个链接，上面描述了我的问题。
Mailcow FORUM - My personal problem
我只是不知道我错在哪里，我希望有人能帮助我。
docker-compose.override.yml

version: '2.1'

services:
    nginx-mailcow:
      networks:
        # Add Traefik's network
        - proxy
      labels:
        - traefik.enable=true
        # Creates a router called "moo" for the container, and sets up a rule to link the container to certain rule,
        #   in this case, a Host rule with our MAILCOW_HOSTNAME var.
        - traefik.http.routers.moo.rule=Host(`${MAILCOW_HOSTNAME}`)
        # Enables tls over the router we created before.
        - traefik.http.routers.moo.tls=true
        # Specifies which kind of cert resolver we'll use, in this case le (Lets Encrypt).
        - traefik.http.routers.moo.tls.certresolver=le
        # Creates a service called "moo" for the container, and specifies which internal port of the container
        #   should traefik route the incoming data to.
        - traefik.http.services.moo.loadbalancer.server.port=${HTTP_PORT}
        # Specifies which entrypoint (external port) should traefik listen to, for this container.
        #   websecure being port 443, check the traefik.toml file liked above.
        - traefik.http.routers.moo.entrypoints=websecure
        # Make sure traefik uses the web network, not the mailcowdockerized_mailcow-network
        - traefik.docker.network=proxy

    certdumper:
        image: humenius/traefik-certs-dumper
    command: --restart-containers ${COMPOSE_PROJECT_NAME}-postfix-mailcow-1,${COMPOSE_PROJECT_NAME}-nginx-mailcow-1,${COMPOSE_PROJECT_NAME}-dovecot-mailcow-1
        network_mode: none
        volumes:
          # Mount the volume which contains Traefik's `acme.json' file
          #   Configure the external name in the volume definition
          - /home/archmatt/traefik/data/acme.json:/traefik:ro
          # Mount mailcow's SSL folder
          - ./data/assets/ssl/:/output:rw
          # Mount docker socket to restart containers
          - /var/run/docker.sock:/var/run/docker.sock:ro
        restart: always
        environment:
          # only change this, if you're using another domain for mailcow's web frontend compared to the standard config
          - DOMAIN=${MAILCOW_HOSTNAME}

networks:
  web:
    external: true
    # Name of the external network
    name: proxy

volumes:
  acme:
    external: true
    # Name of the external docker volume which contains Traefik's `acme.json' file
    name: proxy