Get url: URL must be a valid URL address even though I can reach the URL from other containers.

[neosheo]

Details

I have two docker-compose files one for my media server which includes sonarr and radarr and one for my prometheus which includes exportarr.

Here is a snippet of the compose files:

media server:
  radarr:
    image: lscr.io/linuxserver/radarr:latest
    container_name: media-server-radarr
    environment:
      - PUID=1000
      - PGID=1000
      - TZ=America/Chicago
    volumes:
      - ./radarr/config:/config
      - /mnt/fdrive/Videos/Jellyfin/Movies:/movies #optional
      - /mnt/fdrive/Videos/Jellyfin/Downloads:/data/downloads #optional
    ports:
      - 7878:7878
    restart: unless-stopped
    networks:
      - exportarr

  sonarr:
    image: lscr.io/linuxserver/sonarr:latest
    container_name: media-server-sonarr
    environment:
      - PUID=1000
      - PGID=1000
      - TZ=America/Chicago
    volumes:
      - ./sonarr/config:/config
      - /mnt/fdrive/Videos/Jellyfin/Shows:/tv #optional
      - /mnt/fdrive/Videos/Jellyfin/Downloads:/data/downloads #optional
    ports:
      - 8989:8989
    restart: unless-stopped
    networks:
      - exportarr

`
Then my prometheus compose.yaml:

  exportarr-sonarr:
    image: ghcr.io/onedr0p/exportarr:latest 
    container_name: exportarr-sonarr
    restart: unless-stopped
    environment:
      - PORT=9707
      - URL="http://sonarr:8989"
      - DISABLE_SSL_VERIFY=true
      - APIKEY="REDACTED"
    ports:
      - 9707:9707
    command: sonarr
    networks:
      - exportarr

  exportarr-radarr:
    image: ghcr.io/onedr0p/exportarr:latest
    container_name: exportarr-radarr
    restart: unless-stopped
    environment:
      - PORT=9708
      - URL="http://radarr:7878"
      - DISABLE_SSL_VERIFY=true
      - APIKEY="REDACTED"
    ports:
      - 9708:9708
    command: radarr
    networks:
      - exportarr

  grafana:
    image: grafana/grafana-enterprise:latest
    container_name: grafana
    restart: unless-stopped
    user: "${UID}:${GID}"
    depends_on:
      - grafana-db
    extra_hosts:
      - "smtp.omega.point:192.168.0.23"
    environment:
      GF_DATABASE_TYPE: postgres
      GF_DATABASE_HOST: grafana-db:5432
      GF_DATABASE_NAME: grafana-db
      GF_DATABASE_USER: grafana
      GF_DATABASE_PASSWORD: "${POSTGRES_PASSWORD}"
      GF_DATABASE_SSL_MODE: disable
    volumes:
      - ./grafana/data:/var/lib/grafana
      - ./grafana/config/custom.ini:/etc/grafana/grafana.ini
    ports:
      - 3000:3000
    networks:
      - exportarr

`
I can log into the grafana container and use netcat to verify that the containers in the prometheus compose file can ping and access sonarr at the url http://sonarr:8989 and radarr at http://radarr:7878
What steps did you take and what happened:

What did you expect to happen:
I expected to be able to connect my exportarr instances to sonarr and radarr but the containers just exit with this:

url: URL must be a valid URL address
2024-05-26T19:28:36.182Z        INFO    Starting exportarr      {"app_name": "exportarr", "version": "v2.0.1", "buildTime": "2024-04-05T14:12:42.362Z", "revision": "e8b408abb11c9e0d440b9e51a86e5be8875c45b5"}
Usage:
  exportarr radarr [flags]

`

Anything else you would like to add:

Additional Information: