How to Fix 400 Bad Request Error
By Noah Reed
· About Zone Desire
Quick answer
A 400 Bad Request error means the server could not understand the request, usually because of a wrong URL, oversized or corrupted cookies, or a file that is too large. Check the URL, clear cookies for the site and try again.
What does “400 Bad Request” mean?
HTTP 400 is a client error: the request sent by the browser was invalid.
What causes it?
- Typo or invalid characters in the URL
- Corrupted or too-large cookies
- Uploading a file that is too big
- Stale DNS cache
Steps to try
Stop when the issue is resolved.
- Check the URL for typos or extra characters like % or spaces.
- Clear cookies for that site only.
- Clear browser cache and try incognito.
- Flush DNS: ipconfig /flushdns.
- Upload a smaller file if you were uploading.
Need more support? Check the official help: MDN Web Docs: HTTP response status codes
FAQs
What does 'Request Header Or Cookie Too Large' mean?
It is a type of 400 error caused by big cookies. Clearing cookies fixes it.
Is 400 the website's fault?
Usually it is on the browser side, but a site bug can also cause it.