Ubuntu encountered an error executing the docker-compose command.

  docker, question

Environment: Ubuntu17.10
The following error occurred after executing the docker-compose command:

Couldn't connect to Docker daemon at http+unix://var/run/docker.sock - is it running?
 If it's at a non-standard location, specify the URL with the DOCKER_HOST environment variable.

Then, according to the online method, modify the/etc/default/doc file.
DOCKER_OPTS=”-H tcp:// -H unix:///var/run/docker.sock”
The following figure

After saving and exiting, restart the docker service
sudo service docker restart
View process:

To view the 4243 port status again:

This is the problem, but there is no port 4243 listening at this time! !
Please help me explain how to solve this problem. Thank you all!