What is Mixed Content?
Mixed content occurs when initial HTML is loaded over a secure HTTPS connection, but other resources (such as images, videos, stylesheets, scripts) are loaded over an insecure HTTP connection. Modern browsers display warnings about this type of content to indicate to the user that this page contains insecure resources.
The actual error is similar to this:
How to resolve?
There are may ways to solve this problem, but the real solution is to just request the information using https.
If you are using WordPress, there are many plugins to help you accomplish this easily, one of the most popular ones is Really Simple SSL. This plugin will automatically force HTTPS access to all the files in your website. You may also check out this special made tutorial for WordPress users.
Mixed content with CloudFlare
If you are using CloudFlare with a WordPress website, install their plugin to help you solve this error and add more functionalities:
This plugin will configure your website for correct access through CloudFlare. Find below an article from CloudFlare explaining how to solve the mixed-content problem: