The mixed content error happens when your WordPress website is supposed to be secure (using HTTPS/SSL), but it still serves some stuff, like images or scripts, using an insecure connection (HTTP).
Adding SSL and HTTPS in WordPress is important because it encrypts the info going between your website and people's browsers, making it harder for hackers to grab personal info. Google also prefers secure sites for search rankings.
All the best WordPress hosting companies offer free SSL as part of their packages. If your hosting company doesn't provide that, then you can get free SSL through Let's Encrypt for your WordPress site.
If your SSL is set up right, you will see a little green padlock in the address bar, showing it's secure.
But if not, you might see a broken padlock and a message saying your connection isn't fully secure.
You can find out which content is served through an insecure protocol by using the Inspect tool.
The mixed content error will be displayed as a warning in the console with details for each mixed content item.
Not fixing the mixed content error can make your site more likely to get hacked and cause visitors to not trust your brand. Plus, it could make your site harder to find in search results.
That being said, let's take a look at how to easily fix the mixed content error in WordPress.