This question is a little old, but I got here from Google and it did help me, but I think what I already know can help.
The Issue of Redirection
Anyhoo, to add to user1686's answer, that's a problem where a page on a https url asks for a resource, in this case, the favicon, which redirecting to a non-https url. This is an issue because, for security reasons, browsers will not allow this.
As user1686 says, in Lisa's case, that happens because their website redirects every not found error (404) to a 302 redirect. Although user1686 says that's not a good idea, I think it's pretty common nowadays to have non-existing URLs redirecting to the closest URL, or sometimes to the index page, and, if you're doing maintenance of your website, you might make that a 302 (temporary redirection).
So, how to deal with that? Well, in her case, since her favicon.ico does not exist and that's the start of the problem, uploading the favicon will be enough. But if you're having problems where your https://example.com/favicon.ico
is redirecting to http://example.com/favicon.ico
, you might need to look at your redirecting settings, and where they are is going to depend on your server.
Apache
If you're using Apache, redirection settings are set in your .htaccess
file, and, although you may have many of them, the relevant one will be the one in the root folder of your website (usually called www
or web
). Editing .htaccess is an art in itself, I recommend using these resources.
Nginx
If you're using Nginx, you are going to have to play with the main configuration files, probably using the try_files
and/or the location
directive. You can learn how to use them here. If you don't know where the main configuration file is, it's probably in /etc/nginx
, /usr/local/nginx/conf
, or /usr/local/etc/nginx
.
IIS
If you use Microsoft's IIS, I'm guessing it will have to do with the URL rewrite .NET extension. You can find more about it here.