505

505 HTTP Version Not Supported Error

Category: HTTP Errors | Platforms: apache nginx

What This Error Means

The 505 HTTP Version Not Supported error indicates that the server does not support, or refuses to support, the major version of HTTP that was used in the request message.

Common Causes

  • The server is outdated.
  • The client is using a very new or experimental HTTP version.
  • Misconfigured server software.

How to Fix It (For Users)

  1. 1 Update your web browser.
  2. 2 Try a different browser.

For Site Owners / Developers

  1. Update web server software to the latest version.
  2. Check server configuration for protocol support.
  3. Ensure no proxy is downgrading the protocol incorrectly.

When It Is NOT Your Fault

If the server is running obsolete software.

Check if this outage affects everyone globally

This error often indicates a wider problem. Use our tool to verify if the site is down for everyone.

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