505 HTTP Version Not Supported

Meaning

Server error responses indicate the server failed to fulfill a valid request.

Causes

• Request or response flow is affected by the status meaning.
• Headers or request body may require changes.

How to fix

• Retry after a short delay.
• Contact the site owner if it persists.

Example

HTTP/1.1 505 HTTP Version Not Supported

Official references

IANA HTTP Status Code RegistryOfficialRegistryhttps://www.iana.org/assignments/http-status-codesOpen in new tab MDN HTTP response status codesReferenceDocshttps://developer.mozilla.org/en-US/docs/Web/HTTP/StatusOpen in new tab RFC 9110 (HTTP Semantics)ReferenceSpechttps://www.rfc-editor.org/rfc/rfc9110Open in new tab RFC 9110: 505 status codeReferenceSpechttps://www.rfc-editor.org/rfc/rfc9110Open in new tab

FAQ

• Is this my problem or the server’s? — It depends on the status class (4xx vs 5xx).
• What should I check first? — Start with the request URL, headers, and body.

When to contact support

If it persists, contact the service owner.