'Bad Request: Your client has issued a malformed or illegal request'

.

.

.

'Bad Request: Your client has issued a malformed or illegal request'

Symptoms:
Logging in creates the error 'Bad Request: Your client has issued a malformed or illegal request.'

Cause:
Your browser has a bad or outdated cookie.

Solution:
Clear your browser's cache and cookies. For instructions, please select your browser below:

Firefox

In Firefox for PCs:

1. Log out of Gmail and close all other open browser windows.
2. Click the Tools menu at the top of your browser and select Clear Private Data...
3. Select the Cookies and Cache checkboxes.
4. Click Clear Private Data Now.

In Firefox for Macs:

1. Log out of Gmail and close all other open browser windows.
2. Click the Firefox menu at the top of your browser and select Preferences...
3. Select the Privacy tab.
4. Click Clear Now... at the bottom of the dialogue box.
5. Check the boxes next to Cache and Cookies in the new dialogue box.
6. Click Clear Private Data Now.

Internet Explorer

In Internet Explorer 6.x:

1. Log out of Gmail. Close all other open browser windows.
2. Click the Tools menu at the top of your browser, and select Internet Options.
3. Click the General tab at the top of the dialogue box.
4. Click Delete Files under Temporary Internet files.
5. Select Delete all offline content by checking the box.
6. Click OK.

In Internet Explorer 7:

1. Log out of Gmail and close all other open browser windows.
2. Click Tools > Internet Options.
3. Select the General tab.
4. Click Delete under Browsing History.
5. Under Temporary Internet Files, click Delete Files.
6. Click Delete Cookies.
7. Click OK.

Mozilla

In Mozilla:

1. Log out of Gmail. Close all other open browser windows.
2. Click the Edit menu at the top of your browser, and select Preferences.
3. Click the + next to Advanced.
4. Select Cache under Advanced.
5. Click Clear Cache.
6. Click OK.

Netscape

In Netscape:

1. Log out of Gmail. Close all other open browser windows.
2. Click the Edit menu at the top of your browser, and select Preferences.
3. Click the + next to Advanced.
4. Select Cache under Advanced.
5. Click Clear Cache.
6. Click OK.

Safari

In Safari:

1. Log out of Gmail. Close all other open browser windows.
2. Open the Safari menu on your browser's toolbar.
3. Select Empty Cache.
4. Click Empty in the dialogue box.

Other browsers

We're sorry, but other browsers are not fully supported by Gmail, and may not work properly with all Gmail features and functions.

We suggest using Google Chrome, Internet Explorer 6+, Mozilla Firefox 1.0+, or Safari 3.0+ for the best Gmail experience.

If clearing your browser's cache and cookies didn't fix the problem, visiting the secure site may resolve the issue.

Gmail offers an encrypted site for extra security. Because browsers are more likely to trust encrypted data, visiting Gmail through its encrypted login will often resolve issues.

Please try logging in to Gmail via https://mail.google.com.