This page contains both secure and nonsecure items (or "Unauthenticated content" or "connection partially encrypted").

Problem:
This happens on all my "secure" pages, such as Login, My Account and Checkout.
When I click the Log In link as a customer i get prompted with the security prompts stating:

"This page contains both secure and nonsecure items.
Do you want to display the nonsecure items?"

or
"Page contains unauthenticated content"

or
"connection partially encrypted"



Solution:

That indicates that somewhere in your templates or stylesheets you have hard-coded actual URL links to http://xxxxxxxxx  instead of using relative paths to objects.

This can also happen if you have added banners with http:// links and not told them to skip display on SSL pages.

This can also happen if you have added click-tracking tools to your site via javascript, which link to http:// pages somewhere.

You can identify most culprits by searching your browser's View Source for:
src="http://

Then work through your template files and stylesheets and remove those hard-coded links. If they are caused by click-tracking scripts somewhere, try converting them to https:// links or contact the vendor for assistance with alternate scripts.


Basically, *never* hard-code a full HTTP:// URL into any page/template/stylesheet on your site unless you know for certain that doing so will not produce this sort of error.  This is especially true for <IMG SRC=...> and <SCRIPT SRC=...> tags.



ANOTHER TIP:
Sometimes these same errors are caused by images mentioned in your stylesheet. Double-check to be sure that all those images actually exist. If they don't, then they'll produce "404 Not Found" errors, and sometimes that'll create a "loop" to attempt displaying a 404-error-page, which can in turn throw even more messages.

And, if you have created a "custom" 404 page, then if *that* page has any missing images referenced on it, or on its stylesheets, you could end up in a loop that not only throws security/encryption errors, but also creates excessive traffic in your hosting account, which will make your hosting company unhappy.