How to Fix the 400 Bad Request Error

The dreaded 400 Bad Request error – an HTTP status code indicating a problem with the request sent to the website server. This often happens when a simple action, like loading a webpage, goes wrong. Let's explore how to troubleshoot this common issue.

Troubleshooting Steps for a 400 Bad Request Error

1. Verify the URL: Double-check the website address for typos or malformed syntax. A simple mistake can trigger this error.

2. Clear Browser Cookies: Corrupted or outdated cookies, especially with Google services, can cause 400 errors. Clear your browser's cookies to resolve this potential issue.

3. Clear Browser Cache: A corrupted cached version of the webpage might be the culprit. Clearing your cache is a quick fix worth trying, though it's not always the solution.

4. Flush DNS Cache: Outdated DNS records can cause this error. In Windows, open Command Prompt and run: ipconfig /flushdns

5. Consider a 504 Gateway Timeout: In rare cases, a slow server communication (gateway timeout) might incorrectly manifest as a 400 Bad Request. Investigate this possibility.

6. Check File Size (for uploads): If uploading a file, the server might reject it due to its size. Compress the file (e.g., using a ZIP archive) and try again.

7. Check Your Internet Connection: If the error occurs on multiple websites, the problem might be with your computer or internet connection. Run a speed test and contact your ISP.

8. Contact the Website: The issue might lie with the website itself. Contact the website's support team to report the error.

9. Try Again Later: If all else fails, the problem may be temporary on the server-side. Check back later.

Variations of the 400 Bad Request Error

The 400 error can appear in various forms:

• 400 Bad Request
• Bad Request: Invalid URL
• HTTP Error 400. The request hostname is invalid.
• Bad Request: Error 400
• 400 - Bad request... malformed syntax.

The error message displays within your browser window.

Microsoft IIS Specific Error Codes:

Microsoft IIS servers often provide more detailed 400 error codes, such as:

Code	Description
400.1	Invalid Destination Header
400.2	Invalid Depth Header
400.3	Invalid If Header
400.4	Invalid Overwrite Header
400.5	Invalid Translate Header
400.6	Invalid Request Body
400.7	Invalid Content Length
400.8	Invalid Timeout
400.9	Invalid Lock Token

Similar Errors: Other client-side errors (401, 403, 404, 408) are related. Server-side errors (starting with 5) are different.

Causes: While incorrect URLs are common, other factors can also contribute to 400 Bad Request errors.

Smart TV Error 400: If you encounter this error on your smart TV while streaming, try reloading the video, clearing the app cache, logging out/in of the streaming app, and restarting your TV.

This comprehensive guide should help you diagnose and resolve most 400 Bad Request errors. Remember to check the obvious first (URL accuracy) and work your way through the troubleshooting steps.

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