Issues with Gravatar Hovercards and Gravatars in subscriber e-mails

I use the jetpack plug-in along side the Author Avatar List plug in to actually list out the authors on my site. I activated the hover card feature but it hasn’t been working properly, and when it does work it only works for 2 of my authors. Also, for myself and one other author, our gravatars do not end up in the posts that go out via e-mail to our subscribers. Any ideas why these things are happening? Any help you can give would be greatly appreciated.

Thanks!
~Rachel