When sending email notifications, it happens regularly that the message cannot be delivered, for whatever reason. Those emails bounce back from Amazon's email service, with a failure message. Besides a few exceptions, most delivery failures are permanent and Chaturfier will automatically disable email notifications for your account.
If you notice that you're not receiving any email notifications, and the email channel on your account has been disabled, first check if something is wrong with your mail account (like a full mailbox). You also may consider using another mail provider. I've noticed, for example, that emails to gmx.de, gmx.co.uk and web.de all fail consistently. You can change your email address in account settings.
Alternatively consider using another delivery channel, like Twitter or Telegram.