nats-io/nats-server · error

failed to clear deadline: %v

Error message

failed to clear deadline: %v

What it means

HTTP proxy tunnel setup: after a successful CONNECT handshake, clearing the previously set deadline via conn.SetDeadline(time.Time{}) failed, indicating the connection is already in a bad state, so it is closed and the error surfaced.

Source

Thrown at server/leafnode.go:676

	resp, err := http.ReadResponse(bufio.NewReader(conn), req)
	if err != nil {
		conn.Close()
		return nil, fmt.Errorf("failed to read proxy response: %v", err)
	}

	if resp.StatusCode != http.StatusOK {
		resp.Body.Close()
		conn.Close()
		return nil, fmt.Errorf("proxy CONNECT failed: %s", resp.Status)
	}

	// Close the response body
	resp.Body.Close()

	// Clear the deadline now that we've finished the proxy handshake
	if err := conn.SetDeadline(time.Time{}); err != nil {
		conn.Close()
		return nil, fmt.Errorf("failed to clear deadline: %v", err)
	}

	return conn, nil
}

// Connect to a remote leaf node asynchronously (that is, this function will do
// the connect in a go routine).
func (s *Server) connectToRemoteLeafNodeAsynchronously(remote *leafNodeCfg, firstConnect bool) {
	remote.setConnectInProgress(true)
	s.startGoRoutine(func() {
		defer s.grWG.Done()
		if !connectToRemoteLeafNode(s, remote, firstConnect) {
			remote.setConnectInProgress(false)
		}
	})
}

// Connect to a remote leaf node. Should only be invoked from

View on GitHub (pinned to 3a66a489d2)

Solutions

1. Treat as a fatal connection failure and let reconnect logic retry with a fresh connection
2. Check whether the proxy or intermediate is closing connections early
3. Verify no concurrent close of the same conn

When it happens

Trigger: Thrown at server/leafnode.go:676 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of nats-io/nats-server@3a66a489d2 (2026-09-02). Data as JSON: /api/errors/fafa347182edaedd. Report an issue: GitHub.