Solutions to common problems.

Browser cannot open Green Metrics Tool Frontend / ERR_CONNECTION_REFUSED

When you are getting an unexpected result when accessing localhost / *.internal domain or a different website gets served / 404 / 403 check:

  • Caching problem, please open Developer tools in your browser and check the Disable Cache option under Network
  • Not having the hostname set correctly in /etc/hosts for development: green-coding-postgres-container

  • Not accessing the Green Metrics Tool with the additional supplied port:
  • It could be that you have other containers running and the port is overloaded, so that some other service serves content on that port. Check your docker ps -a
  • Also check lsof -i | grep PORTNUMBER to look if something on your host OS is serving content on that port


  • Hostname of container correct? docker ps tells you the container name, which is also the hostname
  • Are the containers on the same network? Check with docker inspect CONTAINER_ID
  • Can access the container through browser when mapping the ports to the host OS? (See also debug mode for this)

Run fails because volumes, environment or ports are in the usage_scenario.yml

  • If you just copied your docker-compose.yml and wanted to reuse it but do not need the functionality, then consider using the --skip-unsafe flag.
  • If you need the functionality then consider the --allow-unsafe flag

Submodule issues

If you run into any conflicts just deinit and reinit the submodule in question:

git submodule deinit FOLDER -f
git submodule update --init FOLDER
git submodule init FOLDER

General tips

  • Always check container logs with docker compose logs. Sometimes streaming logs does not work that well when orchestrating multiple containers and polling the directly gives you all logs.
  • Add the --debug switche to your local calls to the to enter the stepping debug mode of the tool.
  • Add --allow-unsafe to the call to and ports to your usage_scenario.yml → to access containers through your browser in the host OS to check if the containers are delivering the expected output.
  • Rebuild the containers with docker compose down -v and then docker compose up -d
  • Re-run the script to get new configuration changes that you maybe have not yet applied after an update