Here are all known errors or updates since the course was recorded.
If you are running Docker Toolbox (Windows Home editions or pre-Windows 10), then "localhost" will not work. Find out your docker IP address with "docker-machine ip" and then use this IP address in your browser.
In the video where we run a tomcat container using the command
docker container run -d -p 80:8080 tomcat
This will download whatever image is currently tagged as the :latest. This isn't actually a good idea, because that image can be changed over time - so you can never be sure exactly what version you're going to get!
At the time of writing this errata, this is a real problem - because for some reason the latest image is broken.
So: if you receive a 404 error "The origin server did not find a current representation for the target resource or is not willing to disclose that one exists.", then you can instead run the following:
docker container run -d -p 80:8080 tomcat:8.5.16-jre8-alpine
This will fix the version of the image to be exactly the same as the one I used on the video - so you should get exactly the same results!
Don't make the same mistake as me - in real life, always try to specify the version of the image, and avoid using ":latest". This allows you to control the environment, which is the point of using Docker!