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How To Fix 400 Bad Request Error in WordPress

400 Bad Request, a.k.a. 400 Error, is a client error message that can appear on your WordPress website on several occasions.

Unlike Error 503 Service Unavailable, Bad Request is a client-side error, which means that there is an issue with the request that you sent to the server containing the web page you want to browse.

Although annoying, there are several steps you can undertake to fix the problem and ensure your site visitors can browse your web content uninterrupted.


How To Fix 400 Bad Request Error in WordPress

There are several issues that might result in WordPress displaying the error message. These might be:

  1. Invalid characters in the URL.
  2. Cluttered browser cache and cookies files.
  3. Issues caused by Internet browser extensions.
  4. Uploading a file that is too large.


Method 1: Check for Invalid characters in the URL

Commonly, a Bad Request error message can be displayed after an incorrectly typed URL. However, unlike the case with Error 404 Page Not Found, when we talk about Error 400, the idea is that there are some illegal characters that the server can’t process such as {, }.

So, one of the quick ways to fix the problem is by checking the URL and seeing whether you’ve accidentally typed down a symbol that shouldn’t exist.

Once you’ve fixed the URL, try loading the page again. If you manage to open it, then you have fixed the issue.

If not, proceed with the next step.


Method 2: Clear Your Browser Cache

Sometimes the problem might be way too much cache stored on your Internet browser. To see whether this is the case, clear your cached files and cookies and try to reload the page.

Here’s how to do so, depending on the browser you are using:

  1. Google Chrome

Open the browser and head toward the three-dotted button in the upper right corner. From there go to More Tools->Clear Browsing Data. Then follow the instructions.

  1. Mozilla Firefox

Open Firefox and click on the three lines icon (the hamburger button) located at the top right of the screen. Then go to Preferences->Privacy & Security->Clear Data. Follow the instructions and make sure to include cache and cookies in the clearing process.

  1. Microsoft Edge

In case you are using Edge, open it and click on the three dots icon at the top right and from there go to Settings->Clear Browsing Data->Choose What to Clear->select Cookies and Cached files.

  1. Safari

Go to History->Clear History and make sure to select All History of the suggested options. Then delete cache and cookies.


Now, after you’ve deleted cached files and cookies, try to reload the page. If you no longer see the Bad Request error message, then you have managed to fix the issue.

If you still see it, however, proceed with the next step in the process.


Method 3: Deactivate Your Internet Browser Extensions

Sometimes the cause of the error can be rooted in your browser add-ons. This might happen in case some of the extensions interfere with the requests your browser makes towards the server.

To find out whether this is the case, deactivate all your extensions and try to open the page again. If you can open it and browse the content freely, then the issue lies somewhere among the add-ons.

To find out where exactly, turn them on one by one and see whether you can load the page. If you can, then proceed with the next plugin and repeat this process until you find out the one causing the problem. When you do so, deactivate it and report the issue to the respective developers.


Method 4: Reduce the Size of the Uploaded File

If you are trying to upload a file, which happens to be way too large, the server might reject it and force WordPress to display the Bad Request Error message.

To avoid such issues, make sure to optimize your content and try to compress the media files before uploading them to your WordPress. By doing so, you will minimize the chance of being rejected by the server to a minimum.



Although annoying, Error 400 Bad Request Error can point you to some issues on your WordPress website that you can fix almost instantly with only a few clicks here and there.

Furthermore, fixing Error 400 doesn’t require some special knowledge in programming or coding, only a simple understanding of several website-building and maintenance concepts.

Speaking of site-building, if you are new to WordPress and want to learn how to build your first site, then look no further than our comprehensive and completely free step-by-step WordPress guide. There you will find everything you need to craft elegant pages and beautiful websites.



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