使用Traefik时无法连接到其他容器

Question

我正在尝试“混合”使用暴露于Internet的Traefik的容器和不使用Traefik的容器，这些容器仅在我的LAN端可用。但是我遇到了一个问题，似乎我无法将未使用Traefik的容器与使用Traefik的容器连接。

version: "3.6"
services:

  traefik:
    hostname: traefik
    image: traefik:latest
    container_name: traefik
    restart: always
    domainname: ${DOMAINNAME}
    networks:
      - default
      - traefik_proxy
    ports:
      - "80:80"
      - "443:443"
      - "8080:8080"
    environment:
      - CLOUDFLARE_EMAIL=${CLOUDFLARE_EMAIL}
      - CLOUDFLARE_API_KEY=${CLOUDFLARE_API_KEY}
    labels:
      - "traefik.enable=true"
      - "traefik.backend=traefik"
      - "traefik.frontend.rule=Host:traefik.${DOMAINNAME}"  
#      - "traefik.frontend.rule=Host:${DOMAINNAME}; PathPrefixStrip: /traefik"
      - "traefik.port=8080"
      - "traefik.docker.network=traefik_proxy"
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock:ro
      - ${USERDIR}/docker/traefik:/etc/traefik
      - ${USERDIR}/docker/shared:/shared

  mariadb:
    image: "linuxserver/mariadb"
    container_name: "mariadb"
    hostname: mariadb
    volumes:
        - ${USERDIR}/docker/mariadb:/config
    ports:
      - target: 3306
        published: 3306
        protocol: tcp
        mode: host
    restart: always
    environment:
      - MYSQL_ROOT_PASSWORD=${MYSQL_ROOT_PASSWORD}
      - PUID=${PUID}
      - PGID=${PGID}
      - TZ=${TZ}

  nextcloud:
    container_name: nextcloud
    depends_on:
      - traefik
      - mariadb
      - redis
    restart: always
    image: linuxserver/nextcloud
    volumes:
      - ${USERDIR}/docker/nextcloud:/config
      - ${USERDIR}/shared_data:/data # Path to data you want to share/sync
      - ${USERDIR}/docker/shared:/shared
#    ports:
#      - "XXXX:443"
    environment:
      - PUID=${PUID}
      - PGID=${PGID}
    networks:
      - traefik_proxy
      - default
    labels:
      - "traefik.enable=true"
      - "traefik.backend=nextcloud"
      - "traefik.frontend.rule=Host:nextcloud.${DOMAINNAME}"
      - "traefik.port=443"
      - "traefik.protocol=https"
      - "traefik.docker.network=traefik_proxy"

networks:
  traefik_proxy:
    external:
      name: traefik_proxy
  default:
    driver: bridge

我可以通过nextcloud.example.com到达我的nextcloud容器，也可以到达traefik子域。因此traefik似乎已启动并运行。

如果我执行$ docker-compose ps，则mariadb已启动 mariadb /init Up 0.0.0.0:3306->3306/tcp

还有nextcloud nextcloud /init Up 443/tcp, 80/tcp

我尝试将网络traefik_proxy添加到mariadb，没有运气，并且尝试将默认网络添加到nextcloud。