XTLS/Xray-core · error

failed to dial to %s

Error message

failed to dial to %s

What it means

fetchHTTPContent performs the GET with a 30s-timeout client and wraps transport failure as "failed to dial to <target>". Note the underlying error is discarded, so network vs DNS vs TLS problems are indistinguishable from the message alone. Only http/https targets reach this point.

Source

Thrown at main/commands/all/api/shared.go:95

	parsedTarget, err := url.Parse(target)
	if err != nil {
		return nil, err
	}

	if s := strings.ToLower(parsedTarget.Scheme); s != "http" && s != "https" {
		return nil, fmt.Errorf("invalid scheme: %s", parsedTarget.Scheme)
	}

	client := &http.Client{
		Timeout: 30 * time.Second,
	}
	resp, err := client.Do(&http.Request{
		Method: "GET",
		URL:    parsedTarget,
		Close:  true,
	})
	if err != nil {
		return nil, fmt.Errorf("failed to dial to %s", target)
	}
	defer resp.Body.Close()

	if resp.StatusCode != 200 {
		return nil, fmt.Errorf("unexpected HTTP status code: %d", resp.StatusCode)
	}

	content, err := buf.ReadAllToBytes(resp.Body)
	if err != nil {
		return nil, errors.New("failed to read HTTP response")
	}

	return content, nil
}

func showJSONResponse(m proto.Message) {
	if isNil(m) {
		return

View on GitHub (pinned to 7d214f8b09)

Solutions

1. Verify reachability independently: `curl -v <url>` from the same machine/user
2. Fix DNS (switch resolver) or route egress through a working proxy
3. If TLS/clock related, fix system time or CA store
4. Consider hosting the resource (e.g. geoip.dat) locally to avoid the remote fetch

Example fix

# diagnose (the error intentionally hides the cause)
curl -v https://example.com/geoip.dat
# then fix DNS/proxy/egress accordingly

// pre-flight reachability check with the real cause preserved
func reachable(target string, timeout time.Duration) error {
    u, _ := url.Parse(target)
    conn, err := net.DialTimeout("tcp", u.Host, timeout)
    if err != nil { return err }
    return conn.Close()
}

var body []byte
err := backoffRetry(3, func() error {
    var e error
    body, e = fetchHTTPContent(target)
    return e
})
if err != nil && strings.Contains(err.Error(), "failed to dial") {
    // error hides the cause — re-diagnose out-of-band with curl before retrying further
}

When it happens

Trigger: DNS resolution failure, connection refused/timeout, TLS handshake error, or firewall block while fetching remote content (geodata files, API endpoints) from the xray CLI.

Common situations: Blocked regions needing a proxy for outbound HTTPS; stale DNS; server down; egress firewall in containers; system clock skew breaking TLS certificate validation.

Related errors

• failed to dial to
• unexpected HTTP status code: %d
• LRU size is bigger than subnet size
• No available name server could be created from
• failed to create unexpected ip matcher

AI-assisted analysis of XTLS/Xray-core@7d214f8b09 (2026-08-15). Data as JSON: /api/errors/f4a6ddd8c2c94f0e. Report an issue: GitHub.