Travis Fails - error: Cannot connect to the Docker daemon at unix:///var/run/docker.sock

Hello.
Has anyone seen this error?

$ docker run -it --rm -e {SOME_ENV_PARAMS}
demo_frontend:1.0-frontend nginx -t
docker: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?.
See 'docker run --help'.
The command "docker run -it --rm -e {SOME_ENV_PARAMS}
demo_frontend:1.0-frontend nginx -t" exited with 125.

How did you fix this issue?

An error started on some jobs yesterday. Until yesterday, these jobs passed successfully.