Header Error Troubleshooting

Occasionally, when trying to access a library resource or database, your web browser may show a 431 Error stating: “Request Header Fields Too Large. The server refused this request because the request header fields are too large.” Other times, a database may simply stop loading or responding.

This specific error is likely caused by browser cookies – your browser is faithfully sending all the cookie data with each request to the server, as expected. However, that amount of data exceeds the amount allowed by that server…something of a cookie pile-up.

There are two ways to get around these errors:

  1. Open the desired page in a different browser OR use a private/incognito window in your current browser.
  2. Clear your browser’s cookies.
A “cookie pile-up”

Clearing all cookies will log you out of all accounts you may have open and that can be a pain. Instead, you can opt to just remove the cookies pertaining to wisc.edu. Here is how to remove specific cookies on various browsers:

  1. While using Chrome, go to the library homepage.
  2. In the URL address bar, click the Site info button Default (Secure)  and choose “Cookies and Site Data”.
  3. Choose “Manage On-Device Site Data” and a smaller window will open showing active cookies.
  4. Delete each .wisc.edu cookie by clicking the trash icon.
  1. While using Firefox, go to the library homepage.
  2. In the URL address bar, click the padlock icon and choose “Clear Cookies and Site Data”.
  1. Go to Safari > Preferences > Privacy > Manage Website Data.
  2. Choose all wisc.edu sites and select Remove.