Running your WordPress site over HTTPS is no longer optional. 🔒 Not only is it more secure (everything is encrypted, nothing passed in plain text), but it also builds trust, is an SEO ranking factor, and provides more accurate referral data. Performance issues tied to encryption have been fixed for the most part thanks to HTTP/2 and Let’s Encrypt has changed the entire industry by providing you with an easy way to get free SSL certificates.
For some businesses though, one of the most important reasons is that web browsers such as Chrome and Firefox are cracking down on those not running over HTTPS and showing stricter warnings. That’s the last thing you want your visitors to see!
(Suggested reading: if you’re using legacy TLS versions, you might want to fix ERR_SSL_OBSOLETE_VERSION Notifications in Chrome).
We have an in-depth guide on how to migrate from HTTP to HTTPS, and a very common problem website owners encounter afterward is “mixed content warnings.” Today we’ll show you a few different ways you can fix these on your WordPress site.
- What is a Mixed Content Warning?
- What Causes Mixed Content Warnings?
- How to Fix Mixed Content Warnings
What is a Mixed Content Warning?
A mixed content warning appears in a user’s browser when the WordPress site is loading both HTTPS and HTTP scripts or content at the same time. You can’t load both as they are completely separate protocols. When you migrate to HTTPS, everything needs to be running over HTTPS.
Wired actually documented their transition from HTTP to HTTPS and a mixed content warning snag they ran into:
Below are some examples of what happens in the browsers if you don’t fix these warnings.
Chrome Mixed Content Warning Example
Here is an example of what happens in Chrome when a mixed content warning fires on a WordPress site. According to NetMarketShare, Chrome currently leads in the pack in terms of browser market share, being used by over 60% of the web. So the following warning is most likely what most of your visitors would see.
Firefox Mixed Content Warning Example
Here is an example of what happens in Firefox when a mixed content warning fires on a WordPress site.
Microsoft Edge Mixed Content Warning Example
Here is an example of what happens in Microsoft’s Edge browser when a mixed content warning fires on a WordPress site.
Internet Explorer Mixed Content Warning Example
Here is an example of what happens in Internet Explorer when a mixed content warning fires. As you can see, IE is probably one of the worst because it actually breaks the rendering of the page until the popup is clicked. Thankfully, Internet Explorer doesn’t hold that much of the browser market share anymore.
What Causes Mixed Content Warnings?
We’ve found that the most common time mixed content warnings appear is right after someone migrates their WordPress site from HTTP to HTTPS. HTTP links simply get carried over and this causes mixed content warnings to start firing. Another reason could be that you just added a new service or plugin.
Here are some additional examples of what might cause a warning:
- Plugin developers sometimes use absolute paths (
- Images have hardcoded URLs (
http://yourdomain.com/image.png) that point to HTTP. These could be within a post, page, or even a widget.
- Your linking to HTTP versions of external scripts. (Hosted jQuery, Font Awesome, etc.)
- You have embedded video scripts using HTTP instead of HTTPS.
How to Fix Mixed Content Warnings
Follow the simple steps below to fix your WordPress mixed content warnings. This assumes you have already done the following:
We’ll be using our development site (wpdev.ink) in the examples.
The first thing you need to do is find out which resources are still loading over HTTP. Browse to the page where it’s happening and launch Chrome DevTools. Remember, it might only be happening in certain areas of your site, not globally.
- Windows: F12 or CTRL + Shift + I
- MAC: Cmd + Opt + I)
You can also open Chrome DevTools from the tools menu.
There are are a couple places you can check which resources aren’t loading over HTTPS. The first is the “Console” tab. Note: You might need to refresh the page after you have Chrome DevTools open for it to properly load everything.
Below we can easily see that there is an insecure image being linked to an HTTP version of the site and a link pointed to an HTTP hosted version of jQuery.
You can also look in the “Security” tab. It will show you the non-secure origins and you can click to “View the request in the network panel.” Note: You might need to refresh the page after you have Chrome DevTools open for it to properly load everything.
And last but not least, you can view the requests in the “Network” tab. Note: You might need to refresh the page after you have Chrome DevTools open for it to properly load everything.
If you aren’t using Chrome, or just want a quick summary of the errors, you can also use a free tool like Why No Padlock. It scans an individual page and shows you all of the insecure resources.
Checking HTTPS Warnings in Bulk
If you’re worried about the rest of your site you might want to check it in bulk. Here are some recommended options.
- There is a free little tool called SSL Check from JitBit which you can use to crawl your HTTPS WordPress site and search for insecure images and scripts that will trigger a warning message in browsers. The number of pages crawled is limited to 200 per website.
- The Ahrefs audit tool now has the ability to detect HTTPS/HTTP mixed content. If you already have access to this, or someone on your marketing team does, this can be a great way to be thorough.
- HTTPS Checker is desktop software you can install that will scan your site. It can help you check for “not secure” warnings and content after big changes. It is available on Windows, Mac, and Ubuntu. The free plan allows you to check up to 100 pages.
The next step is confirming that those resources loading over HTTP are accessible over HTTPS. They most likely are, you just need to update the links. If our example above we’ll use the insecure image and hosted jQuery.
If we take both of those URLs, input them into our browser’s address bar, and append HTTPS on the beginning, we can see that they load just fine. Therefore we simply need to proceed to do a search and replace on our site.
There are are a lot of different ways in which you can perform a WordPress search and replace. In this post, we will walk you through two different recommended options.
If you’re curious, we don’t recommend using the Really Simple SSL plugin. While it’s a great plugin, you shouldn’t rely on a plugin like this long term. You won’t be migrating back to HTTP later, so do it the right way and update your HTTP URLs in your database (as we’ll show you below).
If you’re a Kinsta client, you can use our search and replace tool that is available from right within the MyKinsta dashboard. Go to your site’s “Tools” page and click on Search and Replace.
- In the search field, enter the value you want to search for in the database. In this case, we will use our HTTP domain:
- Click the “Search” button to run a search on the database. The search and replace tool will show the number of occurrences for the given string.
- Check the “Replace” box to continue with the replacement process. In the replace with field, enter the value that should be used to replace the value you are searching for. In this case, we will use our HTTPS domain:
- We recommend leaving the “Clear cache when ready” box checked to automatically purge Kinsta Cache after the search and replace process.
- Click the “Replace” button.
Important: Ensure you don’t include any leading/trailing whitespace in either of the fields as this might produce undesirable results.
If you aren’t a Kinsta client, you can do this same task with the free Better Search Replace plugin and then simply delete the plugin after you’re done.
You can download it from the WordPress repository or by searching for it within your WordPress dashboard under “Add New” plugins. After activating it just search for your HTTP domain (http://yourdomain.com) and replace with your HTTPS domain (https://yourdomain.com).
For most of you a simple search and replace should quickly resolve your mixed content warnings and have your site back to normal in just a few minutes. If it doesn’t fix everything, it’s most likely there are one or two scripts left behind that are hard coded. For these, you’ll need to find them and manually update them.
If you have any feedback or run into any issues, let us know below in the comments.
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