Solved
Where to configure associate domains?
I'm trying to follow this article to configure our domain but I don't see that option.
I'm the admin and even the owner can't see it.
Was this functionality moved to another place?
Thanks!
Right there is the problem: you've got a Pro account. Please re-read the prerequisites section of the document you referenced:
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.