Whenever I receive an html email, I have a completely empty email with the top bar that says "External images are not displayed. Display Images". When I click on display images nothing happens. Whether it's the preview pane or not the images (or text) will not load.

If I hit reply to that message it will show the text in my quoted reply. Is anyone else having this issue?

Zimbra OSS 4.0.1
Firefox 1.5.0.5