Then you should be able to do like I said and it might solve whatever is happening. I also have both homepage and paperless in the same docker-compose file. If you set the container name for each container then you can just reference that in homepage widgets. For example here is my homepage and paperless:

homepage:
    image: ghcr.io/gethomepage/homepage:latest
    container_name: homepage
    restart: unless-stopped
    environment:
      - PUID=1000
      - PGID=1000
      - TZ=Europe/Berlin
    volumes:
      - /opt/docker/homepage:/app/config
      - /var/run/docker.sock:/var/run/docker.sock:ro # (optional) For docker integrations)

  paperless:
    image: ghcr.io/paperless-ngx/paperless-ngx:latest
    container_name: paperless
    restart: unless-stopped
    depends_on:
      - paperless-redis
      - postgres
    networks:
      - proxy
    user: "1000"
    environment:
      - USERMAP_UID=1000
      - USERMAP_GID=1000
      - TZ=Europe/Berlin
      - PAPERLESS_REDIS=redis://paperless-redis:6379
      - PAPERLESS_TIKA_ENABLED=1
      - PAPERLESS_TIKA_GOTENBERG_ENDPOINT=http://gotenberg:3000/
      - PAPERLESS_TIKA_ENDPOINT=http://tika:9998/
      - PAPERLESS_DBENGINE=postgresql
      - PAPERLESS_DBHOST=postgres
      - PAPERLESS_DBNAME=paperless
      - PAPERLESS_DBUSER=paperless
      - "PAPERLESS_DBPASS=password
    volumes:
      - /opt/docker/paperless/data:/usr/src/paperless/data
      - /opt/docker/paperless/export:/usr/src/paperless/export
      - /opt/docker/paperless/consume:/usr/src/paperless/consume
      - /mnt/paperless:/usr/src/paperless/media

so both have conatiner_name set to the same string as the service name. And in my homepage widgets I just use the container name in the URL, example:

    - Paperless:
        icon: paperless-ngx
        href: https://paperless.local.tld/
        widget:
            type: paperlessngx
            url: http://paperless:8000/
            username: username
            password: password

This only works if they are in the same docker network. If you don’t explicitly set the network for the containers and they are in the same compose file then they should be in the same network.