Ahhhhh! Obviously, it was a dumb thing. But I found it!!
On page #2 of the tutorial, Ashley suggest to untick "Public". But if, like me, your network is not setup properly, then maybe you can try to actually keep it tick.
Side note: If you already created the rule, no need to create a new one. Go in your Advanced Firewall Settings, and fin the rule you created before. Double-click it and go to the "Advance" tab to tick the "Public" checkbox.
Hope this will help other people!