docker-machine - Error attempting heartbeat call to plugin server: connection is shut down

Question

I have fired up a docker-machine in MacOS, after I ssh into it and create some containers everything is running fine. I can see everything working as it should, even bashing into the containers is still fine there are no errors on start.

My issue comes later on as I leave myself ssh'd into the machine after some time I get this error repeating itself over and over again. This will even happen if I leave myself ssh'd in a docker container for long enough.

What is going on here?
example image

Temporary Solution: exit and re-ssh into the docker-machine

Answer 1

I was getting this error all of a sudden as well and it didn't go away until I restarted the virtualbox instance docker-machine restart default

Answer 2

i found that there is no need to restart the docker machine. just quit the terminal window/tab and starts another one. all is good for me.