"docker exec" and "docker start" fails to find container

I’m new to docker and created an image from a repository that includes a “dockerfile”.
The build process ended successfully generating an image ID of 295e7c040cc2.
When I try to run “docker exec -it 295e7c040cc2 /bin/bash”, I get an error:

Error: No such container: 295e7c040cc2

Running “docker images” shows that the image exists.

Why is this happening?

Source: StackOverflow