I encountered this same problem with a new installation of Ubuntu 22.04.1 LTS using R2022a or R2022b.
I performed the same checks as specified by SG. What I believe was missed is that the Docker service was not running.
Most likely, the docker commands were installed but not the service. I used a snap to install Docker.
sudo snap install docker
But that snap does not include the Docker services. Run the following command to verify that Docker services are not available:
sudo systemctl status docker
That will report "Unit docker.service could not be found.". To add the Docker services I followed the instructions from a tutorial on HowtoForge.com titled "How to create Docker Images with a Dockerfile on Ubuntu 20.04 LTS", While this is listed as Ubuntu 20.04 LTS the instructions for the services also apply to 22.04 LTS.
I executed the following commands:
sudo apt update
sudo apt install docker.io
sudo systemctl start docker
sudo enable docker
After enabling the Docker services I was able to successfully build my container.
NOTE: The container will be built with a Ubuntu 20.04 base image.
