(sad) What causes my embed videos to show my clients "Access denied" and how to stop it?

(sad) What causes my embed videos to show my clients "Access denied" and how to stop it?

http://content.screencast.com/users/jalexistt/folders/Jing/media/68f2c180-a33d-4580-abc7-e1445411bf8f/2012-11-28_1653.png

While writing this post, they magically reappeared.

http://screencast.com/t/sg9xtRkT

Is there a glitch?