Hey @danilo.vetturini,
Welcome to the Auth0 community!
You are right, the link in the article is no longer working because it refers to a previous version of the repo. Thank you for reporting 
I’m in the process of updating the current MAUI content because now we have a MAUI SDK, which simplifies significantly the code. This article still uses the previous approach and, as said, points to a repo that has been updated.
I have temporarily fixed the link now, but I plan to update the article in about a week or so.
Stay tuned!