Network timed out while trying to connect to https://index.docker.io

I installed Docker-Toolbox just now while following their webpage

I started with Docker QuickStart Terminal and see following

                        ##         .
                  ## ## ##        ==
               ## ## ## ## ##    ===
           /"""""""""""""""""\___/ ===
      ~~~ {~~ ~~~~ ~~~ ~~~~ ~~~ ~ /  ===- ~~~
           \______ o           __/
             \    \         __/
              \____\_______/


docker is configured to use the default machine with IP 192.168.99.100
For help getting started, check out the docs at https://docs.docker.com

bash-3.2$ 

But when I try to perform docker pull hello-world, this is what I see

bash-3.2$ docker run hello-world
Unable to find image 'hello-world:latest' locally
Pulling repository docker.io/library/hello-world
Network timed out while trying to connect to https://index.docker.io/v1/repositories/library/hello-world/images. You may want to check your internet connection or if you are behind a proxy.
bash-3.2$ 

What's wrong?

I had the same problem this morning and the following fixed it for me:

$ docker-machine restart default      # Restart the environment
$ eval $(docker-machine env default)  # Refresh your environment settings

It appears that this is due to the Docker virtual machine getting itself into a strange state. There is an open github issue here

I installed Docker without the Toolbox on Windows 10, so the version that requires Hyper-V to be enabled.

For Docker version 1.12 I had to go into the taskbar, right click the Docker Icon, select Settings -> Network and set the DNS Server to fixed, so that is uses Google's DNS server at 8.8.8.8.

Once that setting was changed, it finally worked.