BFA Subscribe with Feedburner - Email subscriptions stopped working

Hi, I've been successfully using BFA Subscribe with Feedburner for many months. Then just recently it stopped working. No changes have been made to the settings since it was first set up over a year ago, so I'm not sure what's going on.

I ran a test by signing up as a new subscriber through the blog, and I received an email confirmation. So that works. But for the past few postings, nobody (including all of my own email addresses) has received email notification.

Any idea what could be happening? Thanks.

www.davidsfitnessforlife.com