Notification on replies to subscribed threads not working?

In my user options, I have instant notification turned on but I don't receive an email when a new reply has been posted. This has not always been this way. Any ideas?

Administrator?

Sorry to see you're getting no response on this. I've got my account set to instant notification and I get emails for replies no problem.

So do I. Maybe send a PM to one of the moderators/admins so that they can look into it.