Encrypted Page Errors
Some computers may display a mixed content message. The box that pops up (Figure 1) will read, "You have requested an encrypted page that contains some unencrypted information. Information that you see or enter on this page could easily be read by a third party." The checkbox text is "Alert me whenever I'm about to view an encrypted page that contains some unencrypted information."
When it presents itself the first time (on Preview), the attached pop-up appears with the checkbox unchecked by default. To close this message click OK, and the warning will never appear again.