If you are using a Proxy Server to access the internet, you have to add the Proxy Server information to the docker container.
In the file settings.conf (which is located on the Simplifier server, inside the docker), you can add the Proxy Server information, for example:
proxy { host: "localhost" port: 3128 byPassUrls: [ "google.de", "login.microsoft.com", "localhost" ] }
Save the file and start the docker or continue with the docker configuration.