Using DNN 6.0

I have two pages on a site that are under SSL.

On one page the "lock" appears as it should.

In the other page, the lock flashes while the page is loading, then disappears. The page remains under 'https://', just no lock.

Any idea why the lock disappears?

Thanks

Thanks Sebastian

Yes, I've cleared cache and cookies but it still errors.

In FireFox, on the page where SSL is not working properly, there is a red circle/slash through the lock and this message when I cilck the lock:  "This web site does not supply ownership information."

However on the other page in the site that's under SSL, no red circle over the lock or message. The SSL works perfectly on that page.