We're implementing the new subscribe button on our webpage, one thing we were noticing straight away was that at a few profiles the subscribe button is not showed, it it possible the button is not integrated in all profiles yet?
@Igy has the correct answer. However finding where to turn on subscriptions is not easily found. It does not seem to be in your user or privacy settings. It can however be found here, and is a big green button if it is not turned on. Good luck with trying to find out where to turn it off!