Billionmail/BillionMail · error

SMTP port must be between 1 and 65535

Error message

SMTP port must be between 1 and 65535

What it means

validateAlertSettings rejects blacklist alert SMTP settings whose port is outside the valid TCP range. SMTPPort must be an integer from 1 to 65535; anything below 1 (typically the zero-value of an unset field) or above 65535 fails validation before any connection is attempted.

Source

Thrown at core/internal/controller/settings/settings_v1_set_blacklist_alert_settings.go:80

	res.SetSuccess(public.LangCtx(ctx, "Alert settings saved successfully and test email sent"))
	return res, nil
}

func validateAlertSettings(settings *v1.SetBlacklistAlertSettingsReq) error {
	if settings.SenderEmail == "" {
		return fmt.Errorf("sender email is required")
	}

	if !strings.Contains(settings.SenderEmail, "@") {
		return fmt.Errorf("invalid sender email format")
	}

	if settings.SMTPServer == "" {
		return fmt.Errorf("SMTP server is required")
	}

	if settings.SMTPPort < 1 || settings.SMTPPort > 65535 {
		return fmt.Errorf("SMTP port must be between 1 and 65535")
	}

	if settings.SMTPPassword == "" {
		return fmt.Errorf("SMTP password is required")
	}

	if len(settings.RecipientList) == 0 {
		return fmt.Errorf("at least one recipient is required")
	}

	for _, recipient := range settings.RecipientList {
		if !strings.Contains(recipient, "@") {
			return fmt.Errorf("invalid recipient email format: %s", recipient)
		}
	}

	return nil
}

View on GitHub (pinned to fc36c76c05)

Solutions

1. Set SMTPPort to the actual SMTP server port (e.g. 587 for STARTTLS, 465 for implicit TLS, 25 for relay).
2. Ensure the JSON request field is a number, not a string, and is explicitly included in the payload.
3. If port is optional, default it server-side to 587 before calling validateAlertSettings.

Example fix

// before
{"smtpServer":"smtp.example.com","smtpPort":0,...}
// after
{"smtpServer":"smtp.example.com","smtpPort":587,...}

const port = Number(payload.smtpPort)
if (!Number.isInteger(port) || port < 1 || port > 65535) {
  throw new Error(`smtpPort must be an integer 1-65535, got ${payload.smtpPort}`)
}

function isValidPort(p: unknown): p is number {
  return typeof p === 'number' && Number.isInteger(p) && p >= 1 && p <= 65535
}

When it happens

Trigger: Calling SetBlacklistAlertSettings with SMTPPort=0 (field omitted in the JSON payload, so GoStruct zero-value), a negative number, or a value >65535.

Common situations: Client omits smtpPort in the request body; frontend sends the port as a string so it fails to bind and stays 0; a typo like 655360; admin pastes a URL instead of a port.

Related errors

• SMTP password is required
• at least one recipient is required
• hostname format is incorrect
• port must be between 1-65535
• IPv4 network format is incorrect, please use CIDR format (e.

AI-assisted analysis of Billionmail/BillionMail@fc36c76c05 (2026-09-05). Data as JSON: /api/errors/ea97b515e9208900. Report an issue: GitHub.