Yeah, I've seen other people reporting the same thing to Support. What I would do is check to make certain that your settings are right and then open a Support request. Make sure you mention that it's the LiveJournal Inbox (because there's currently a problem with notifications not coming to email), and it also helps us investigate if you can mention which notifications you're not getting (from a specific community, from your own journal, etc.)

The other support requests seem to have ended with the user's notifications just mysteriously showing up again, so, I don't know what to tell you.