The HTTP error 431 can occur with many resources and it is an error related to your web browser rather than the resource itself. Typically, the error is caused by issues with cookies set in your browser. Websites often use cookies to store preferences, give relevant content, and keep users signed in. Too many cookies in the request can cause a web page to show the HTTP error 431 status instead of its content
You can normally fix the error by clearing the cookies and browser cache in your web browser.
How to clear browser cache and cookies in different browsers
Important
If you clear all of your browser’s cookies, then you’ll be logged out of every website which has set cookies. If you rely on accessing sites by saved passwords you might want to start by trying to access the resource using a different web browser until you have more time to investigate the cookie settings and check those passwords.