Cannot connect to the Docker daemon

[chri...@codefour.ch]

I am setting up a new Jenkins server under macOS 10.13 from scratch (https://jenkins.io/doc/book/installing/#downloading-and-running-jenkins-in-docker) using the jenkinsci blue ocean docker container. It starts-up and runs ok, but when trying to use any docker commands to pull containers within jenkins I get the error below - am I missing any additional Docker setup inside Jenkins?

+ docker pull python:3.6.3
Warning: failed to get default registry endpoint from daemon (Cannot connect to the Docker daemon. Is the docker daemon running on this host?). Using system default: https://index.docker.io/v1/
Cannot connect to the Docker daemon. Is the docker daemon running on this host?
script returned exit code 1