If you have installed Docker for the first time, it is better to verify the install with the command

docker run hello-world

When you ran that command and got the error “unauthorized: incorrect username or password”, read on. Most likely you would have entered your Docker hub e-mail and password. Big mistake.

The instruction says that you should login with your Docker ID. This Docker ID is not your e-mail. For that you need to login to Docker Hub with your e-mail and go to the Profile page. There you can find your Docker ID.

Go back to your shell prompt and type

docker login

Enter the Docker ID and password and you should get a message that the login succeeded. Now type the first command and it will work

docker run hello-world