How to fix: “Bad Request Error 400″ for Gmail in Google Chrome

If you are signed into multiple Google account for Gmail using Chrome, chances are that you might have encountered the dreaded Bad Request Error 400 error. The error is so frustrating and vague that most users are left clueless on how to fix it. Most importantly, many of us do not have the time to fix the issue when we have to send that all important email. There are a number of forum posts on the Internet in which users mentioned that they have moved to Firefox or other browsers just because of this problem. Its a shame that both the browser and the email are from the provider and they are yet to fix it even though users have had issue for about an year!

But thankfully many users have improvised and found work around to this issue. The problem appears to be with the GMAIL_IMP value stored in the cookie for mail.google.com. No one seems to have an idea what is actually causing the error.  Here I have picked 3 fixes and classified them as the Good, the Bad and the Ugly depending on the complexity of the fix. Lets start with the Ugly… :-)

The Ugly
  1. Right click on the screen.
  2. Select Inspect element.
  3. Select the Resources tab at the top of the Developer Tools window.
  4. Expand the Cookies section in the left side navigation by clicking on the arrow next to Cookies.
  5. Select the mail.google.com cookie.
  6. Right click on GMAIL_IMP.
  7. Select Delete.
  8. Close the Developer Tools window.
  9. Refresh the page giving you the error.
The Bad

(Warning: you will be signed out of all your Google account)

  1.  Get to Chrome Setting.
  2. Click Show advanced settings.
  3. In the Privacy section, click the Content settings button.
  4. In the “Cookies” section, click All cookies and site data to open the Cookies and Other Data dialogs.
  5. In the search box search for mail.google.com.
  6. Click Done
  7. Refresh the page giving you the error.
The Good

Just navigate to any of this URLs

Labs turned on mail.google.com/mail/?labs=1
Labs turned off mail.google.com/mail/?labs=0

This fix is the easiest, but make sure you do this all the time as it will not address the cookie issue.  Better still would be convert your default gmail interface to Gmail Offline. You can read on how to do this here http://techathlon.com/a-better-and-ad-free-gmail-interface/

4 Responses to “How to fix: “Bad Request Error 400″ for Gmail in Google Chrome”
  1. Joshua

    that worked. thank you!

  2. Jim McGregor

    Thanks for The Good fix – worked straight away!

  3. Ronnie

    Thank you!!!!! The ugly was beautiful.

  4. Daniel Moravec

    It worked! Thanks so much for the tips!

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