I am getting the following error when I run circleci build locally on Ubuntu 18.04. The build runs perfectly inside the hosted CircleCI. CircleCI version: Docker-ce version: I installed Docker exactly as specified on the website, including setting the usergroup. I used the instructions here to install CircleCI, which is this command: sudo curl -o /usr/local/bin/circleci https://circle-downloads.s3.amazonaws.com/releases/build_agent_wrapper/circleci && sudo chmod