HTTP version is not supported by the server.

Causes

The server does not support, or refuses to support the major HTTP version that was used in the request message.

Fixes

Step 1: Try A New Version

Try a newer version or switch to a modern browser.

Step 2: Review Those Protocols

The error message should be have indicated what protocols are supported, review those protocols to troubleshoot the error.

Step 3: Upgrade Web Server

Upgrade your Web server software to support the major version of the http protocol require.