@kesiena.akp and @nickhodges I run the last chapter in an Ubuntu VM, started from that chapter cloning the repo and checking out the branch. I was able to get it running. However, I did notice that after you set up the guards, you indeed may get that 401 error. I believe the token needs to be refreshed, so I refreshed the WAB Dashboard app by reloading the page and it worked right away. Could you please try that out? 
I did ask one of my teammates to run the tutorial on this own (someone who has not run this tutorial before) and see if he gets the same blocker as both of you had. I’ll share his feedback once he’s done.
Thank you for your time and for reporting this issue 