This. There are also instances of new users signing up and never receiving their welcome email with signup info or something to that effect. To the point where they need to use a different email host to create an account.Xenforo is really picky when it comes to Gmail for some reason. If you search Google "xenforo gmail notifications", you'll see a bunch of threads on the Xenforo support forums about users not getting notifications with Gmail, and suggestions on how to fix it on the (Xenforo) backend. Unfortunately, with the admins from the site gone, it'll never get fixed here.
You're never going to get it on gmailFYSA - still broken
Searched gmail after 48 hours of waiting for my confirmation email.