Unable to install docker

Hello I have a raspberry pi 4b 4gb running raspbian and need help installing docker. This is what happens when I run the convenience script install.

sudo curl -fsSL https://get.docker.com -o get-docker.sh
pi@raspberrypi:~ $ sudo sh get-docker.sh

Executing docker install script, commit: 26ff363bcf3b3f5a00498ac43694bf1c7d9ce16c

Warning: the “docker” command appears to already exist on this system.

If you already have Docker installed, this script can cause trouble, which is
why we’re displaying this warning and provide the opportunity to cancel the

If you installed the current Docker package using this script and are using it
again to update Docker, you can safely ignore this message.

You may press Ctrl+C now to abort this script.

  • sleep 20
  • sh -c apt-get update -qq >/dev/null
  • sh -c DEBIAN_FRONTEND=noninteractive apt-get install -y -qq apt-transport-https ca-certificates curl >/dev/null
    E: Sub-process /usr/bin/dpkg returned an error code (1)

Why duplicate your issue ?