If you look at the log it clearly shows that docker info is unable to contact the docker pipe
docker run --rm -v \\.\pipe\docker_engine:\\.\pipe\docker_engine appveyor-docker-cli-test docker info
Debug Mode: false
ERROR: error during connect: Get http://%2F%2F.%2Fpipe%2Fdocker_engine/v1.40/info: open //./pipe/docker_engine: Access is denied. In the default daemon configuration on Windows, the docker client must be run elevated to connect. This error may also indicate that the docker daemon is not running.
errors pretty printing info