Since almost everything on the site is done on the client side (probably due to them not wanting to deal with IP bans) the "auth" doesn't actually matter since nobody is veryfying it.
The only thing actually checked is the premium domain access, custom domains work just fine though, I would suggest using that anyway if you care about long term access to the accounts
to unlock all the Account customization options open the browser developer tools and paste this in the console:
localStorage.setItem('settings/auth', '"client side is the safe side ;)"')