YouTube Error 400: Malformed or illegal request [FIX]

Vlad Turiceanu
by Vlad Turiceanu
Editor-in-Chief
Passionate about technology, Windows, and everything that has a power button, he spent most of his time developing new skills and learning more about the tech world. Coming from a solid background in PC... Read more
Affiliate Disclosure
  • YouTube issues such as Your client has issued a malformed or illegal request can prevent you from watching videos online.
  • Fixing this issue is simple, and the first thing you should do is to check if this problem appears in other web browsers.
  • Your cache can also be a cause for this error, so it’s advised to check in order to fix this issue.
  • If YouTube error 400 still appears, be sure to check if the link is correct and check if the browser installation is in order.
your client has issued a malformed or illegal request
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YouTube is the most popular video sharing site in the world. It’s accessed by millions of users every day that upload and search all sorts of video content. Thus, we can say it’s one of the biggest search engines, too.

YouTube was created in 2005, and in October 2006 Google acquired it and transformed it in the giant that is today.

Even though the site is constantly being developed and improved, sometimes some unexpected errors can show up. That’s the case with the Error 400: your client has issued a malformed or illegal request and today we’ll take a look at it.

A lot of users reported the Error 400 in YouTube, and although is an old and known issue, the cause is still a a mystery to Google. Let’s find out how to fix it.

Fixing YouTube error 400: Your client has issued a malformed or illegal request, usually involves clearing all the cookies. The error is mainly caused by shared cookies between YouTube and other extensions. If this action doesn’t solve the problem, you need to clear the specific faulty cookies from Developer tools or use Incognito mode.

It seems that the error is caused by an extension called The Great Suspender. This extension shares the cookies with YouTube and sometimes alters them, leading to the appearance of the Error 400.


How can I fix error 400 in YouTube?

1. Use Opera

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2. Clear the cookies from Chrome’s settings

  1. Open Chrome.
  2. Go to Settings, click Advanced, access Content settings.
  3. Click Cookies, then pick See all cookies and site data.
  4. Type youtube, in the search-bar from the top-right of the page
  5. All the cookies related to YouTube should appear. Click on Remove all shown or choose only the faulty ones called gsScrollPos-[4-digit number].

Alternatively, you can do the same process by opening a new tab in Chrome and by typing in the address bar: chrome://settings/siteData

After doing that, check if Malformed or illegal request message still appears.


3. Clear cookies using Developer Tools

  1. Open Chrome, go to YouTube site.
  2. On your keyboard press Ctrl + Shift + I.
  3. In the Developer Tools click More and then Application.

4. In the left panel, under Storage, expand Cookies, all the cookies should appear.

5. Delete the gsScrollPos-[4-digit number] and the error should be gone.

After following these steps, check if YouTube error 400 your client has issued a malformed or illegal request message is gone.


4. Other general fixes

  1. Use Incognito Mode.
  2. Replace the direct link with the video id.
  3. Clear the full cache and cookies from Clear browsing data in Chrome.

4. Reinstall Chrome.

You can also try these easy and general fixes that fixed YouTube error 400 for some users.


These solutions are relatively simple and you should have no problem solving Error 400: your client has issued a malformed or illegal request. Remember that The Great Suspender extension is the main cause, but it’s not the only one.

We’d like to know your thoughts on this subject so feel free to share them in the comments section below.


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