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What Is HTTP 505 HTTP Version Not Supported?

HTTP 505 HTTP Version Not Supported explained, and what it means when you see it in CI/CD and deployments.

HTTP 505 means the server does not support the HTTP protocol version in the request.

What it means

A 505 is rare; it points to a client using an HTTP version the server cannot handle, or a misconfigured proxy.

When you see it in CI/CD

In CI, a 505 usually means a misconfigured client or proxy forcing an unsupported protocol version. Check client TLS/HTTP settings.

Key takeaways

  • 505 means an unsupported HTTP version.
  • Rare and usually a misconfig.
  • Check client/proxy protocol settings.

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