Bad Request: Request Header or Cookie Too Large

Issue

When accessing a group data sharing site, students with Duo two factor login receive a 400 Bad Request error message with the description Request Header or Cookie Too Large and are unable to log in.

Environment

• Windows
• Mac
• Internet Browser

Resolution

There are a few steps that can be attempted as a workaround or to resolve this problem:

1. You can try to force reload the web page by pressing Ctrl+F5 (Windows) or Command+Shift+R (Mac).
    
2. If the reload of the page doesn't work, the fastest workaround is to open an InPrivate Browsing Window (IE), Incognito Window (Chrome), Private Browsing Window (Firefox), or Private Window (Safari) and visit the site in question. This will not load any cookies or store them after your visit, which circumvents the cause of the problem.
    
3. As a more permanent solution, if you receive this error frequently, the best thing to do is to delete the cookies for that particular domain from your browser's cache.
   • Please refer to the individual article for your browser on clearing your web browser cache.
     • Clearing your web browser cache in Edge
     • Clearing your web browser cache in Firefox
     • Clearing your web browser cache in Safari
     • Clearing your web browser cache in Chrome
   • Or, for Internet Explorer, instructions can be found here.

Cause

When you go to visit a web page, if the server finds that the size of the Cookie for that domain is too large or that some Cookie is corrupted, it will refuse to serve you the web page. Instead, in you browser window, it will show you 400 Bad Request, Request Header or Cookie Too Large.

Additional notes

• https://www.thewindowsclub.com/400-bad-request