Can someone help me

Question

Can anyone tell me how to with thefollowingmessagetrying to access a site " Bad request- Request too Long _ HTTP Error 400. The size of the request header is too long. " I cleared the cache and Browser history and problem persist.

Answer 1

Hi, Hugh Stewart2

Welcome to Microsoft Community and Merry Christmas!

We understand that you have encountered the error message “Bad request- Request too Long _ HTTP Error 400. The size of the request header is too long.” while visiting the website. This is usually because the request header has too much information or is too long for the server to process the request.  Can I ask if you are experiencing this issue when visiting a specific site or all sites?I noticed that you have tried clearing your cache and browsing history but the problem still persists. Then you can also try the following methods:I.Clear Browser CookiesClear cookies manually:- Open your browser settings.- Open your browser settings and find “Privacy, search and services” option.- Select “Clear browsing data now”.- Select Cookies and clear them.*Disclaimer: Your browser automatically saves temporary internet files to help pages load faster. Clearing this cache will sometimes fix website issues. Please back up all your personal files first, such as Favorites, to ensure you do not lose data.*II. Reduce the interference of browser extensionsDisable all extensions:- Open your browser's extensions management page.- Disable all extensions and try visiting the site again.Enable extensions one by one:- If the problem is solved after disabling all extensions, you can enable extensions one by one to find out the specific extension that is causing the problem.- You can also turn on Privacy Mode to exclude extensions from interfering:Open Edge browser, then press crtl+shift+N to visit the website in a new window and see if the same error is still reported.III. Reset Edge Browser-Open “Settings” (you can find it via Start menu or Cortana search).-Click on “Apps”.-In the “Apps & Features” list, find “Microsoft Edge”.-Click on “Microsoft Edge” and then click on “Advanced Options”.-Under the “Reset” section, click the “Reset” button.This will reset Edge to its default state, clearing all personal data and customizations.IV. Try to create a new ProfileOpen Edge and open SettingsIn the Profile screen, click Add Profile in the upper right corner.Test if you still have the same problem in the new Profile.V. Perform a Clean Boot to eliminate the interference of third-party software:How to perform a clean boot in Windows - Microsoft Support*Disclaimer: A “clean boot” starts Windows with a minimal set of drivers and startup programs. It helps to determine whether a background service is interfering with your game or program and to isolate the cause of a problem.**These steps of "clean boot" might look complicated at first glance. However, to avoid any trouble for you, please follow them in order and step-by step so that it will help you get back on track.*VI.Try creating a local account and then try in the local account to see if the problem still exists:Search for CMD, then run it in administrator mode and enter the following commandnet user USERNAME /addnet localgroup administrators USERNAME /addUSERNAME can be replaced with your preferred account name.If there is no problem under the new account, this should be a fault of the account profile, please refer to the following article under Repair Corrupt Profile for the solution to transfer your information to the new account.*Troubleshoot problems signing in to Windows - Microsoft Support*If you have any progress, you are welcome to contact us anytime.

Best Regards

Nicholas.Z - MSFT | Microsoft Community Support Specialist