HTTP 505 HTTP Version Not Supported — What It Means & How to Fix It

Overview

The HTTP 505 HTTP Version Not Supported status code indicates the server does not support the HTTP protocol version used in the request.

Key Details

• The server does not support or refuses to support the major HTTP version in the request.
• The response should indicate which protocol versions the server supports.
• This is rare in practice as most servers support HTTP/1.0, HTTP/1.1, and HTTP/2.
• It may occur with very old clients or experimental protocol versions.

Common Causes

• The client is using an HTTP version the server does not support.
• A very old HTTP/1.0 client connecting to a server that only supports HTTP/1.1+.
• Experimental or draft HTTP version being used.

Steps

1. 1Check what HTTP version your client is using and switch to a supported version.
2. 2Update your HTTP client or browser to support modern HTTP versions.
3. 3Verify the server configuration supports the common HTTP versions.
4. 4Try forcing HTTP/1.1 if the server does not support HTTP/2.

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