Tried really, really hard to follow the published guide you included in this article to set this up - even left a lot of constructive feedback on the article for how it could be improved - but ultimately gave up and resorted to a third party guide. The documentation assumes a lot, is poorly ordered, is missing a lot of specific reasons for why specific steps need to be completed, and appears to throw extra steps in there for no reason (see app registration vs proxy comments - is it 3 or 5?). Please have someone re-write this article, I wasted a lot of time these past couple weeks working through it and in the end burned everything to the ground and got things working with a third party guide in less than a couple hours.
For those that are interested, here's a great guide that walks you through each step in detail: https://blog.hametbenoit.info/2018/02/20/azure-hybrid-cloud-print-service/