Web Browsers - How to Fix a "Bad Request" Error
This document describes what to do if you receive a 400 Bad Request error message upon loading a website.
Problem
When you attempt to access a website, you may sometimes instead receive a "Bad Request" error message where the website content should have loaded. This error often contains the number "400" and may include additional text, such as "Your browser sent a request that this server could not understand. Size of a request header field exceeds server limit."
Solution
First, check the website URL you entered to make sure it is correct. If the web address appears to be entered correctly, then the issue can usually be resolved by clearing your browser's cache and cookies.
For instructions on performing these steps, click on the appropriate link for the web browser you are using:
Windows
| Browser | Document Link |
|---|---|
 Internet Explorer 6 |
Internet Explorer 6 - Windows |
 Internet Explorer 7 |
Internet Explorer 7 - Windows |
Internet Explorer 8 |
Internet Explorer 8 - Windows |
 Internet Explorer 9-11 |
Internet Explorer 9, 10, & 11 - Windows |
 Edge |
Edge - Windows |
 Firefox 3.5 |
Firefox 3.5 - Windows |
 Firefox |
Firefox - Windows |
 Chrome |
Chrome - Windows |
 Opera |
Opera - Windows |
 Safari |
Safari - Windows |
Mac OS X
| Browser | Document Link |
|---|---|
Firefox 3.5 - 20 |
Firefox 3.5 - 20 - Mac |
 Firefox 21+ |
Firefox 21+ - Mac |
Chrome |
Chrome - Mac |
Opera 10.50 |
Opera 10.50 - Mac |
Opera 28 |
Opera 28 - Mac |
Safari 5 |
Safari 5 (and older) - Mac |
Safari 5.1 - 7.9 |
Safari 5.1-7.9 - Mac |
 Safari 8.0+ |
Safari 8.0+ - Mac |
Safari 10.0.1+ |
Safari 10.0.1+ - Mac |
Mobile Operating Systems
| Operating System | Document Link |
|---|---|
 Android |
Android - Chrome |
 iOS |
Safari - iOS |
 webOS |
Web - webOS |
 Windows Phone |
Internet Explorer - Windows Phone |