Finally i managed to make it work.
When I revoked access to the mail demo, it worked. BUT I missed the popups because I clicked them all without reading them.
So when I attempted to get it autorized again, it went back to rejecting it.
Revoking the access to reauthorizing it didn't work.
So I wondered if I had to reauthorize the mail app, so I did it and then I revoked it again.
Then your webapp reauthorized. weird quirks.
In any case, this second time I took a screenshot of every popup: