fatedier/frp · error

not support multiplexer: %s

Error message

not support multiplexer: %s

What it means

Error "not support multiplexer: %s" thrown in fatedier/frp.

Source

Thrown at pkg/config/v1/validation/proxy.go:145

	}
	return errors.New("unknown proxy config type")
}

func validateTCPProxyConfigForClient(c *v1.TCPProxyConfig) error {
	return nil
}

func validateUDPProxyConfigForClient(c *v1.UDPProxyConfig) error {
	return nil
}

func validateTCPMuxProxyConfigForClient(c *v1.TCPMuxProxyConfig) error {
	if err := validateDomainConfigForClient(&c.DomainConfig); err != nil {
		return err
	}

	if !slices.Contains([]string{string(v1.TCPMultiplexerHTTPConnect)}, c.Multiplexer) {
		return fmt.Errorf("not support multiplexer: %s", c.Multiplexer)
	}
	return nil
}

func validateHTTPProxyConfigForClient(c *v1.HTTPProxyConfig) error {
	return validateDomainConfigForClient(&c.DomainConfig)
}

func validateHTTPSProxyConfigForClient(c *v1.HTTPSProxyConfig) error {
	return validateDomainConfigForClient(&c.DomainConfig)
}

func validateSTCPProxyConfigForClient(c *v1.STCPProxyConfig) error {
	return nil
}

func validateXTCPProxyConfigForClient(c *v1.XTCPProxyConfig) error {
	return nil

View on GitHub (pinned to 6c8a8d0a97)

Solutions

1. Set multiplexer to 'httpconnect', which is the only supported value for tcpmux proxies.
2. Remove the multiplexer field if the proxy type does not need it.

When it happens

Trigger: Raised by validateProxyConfigForClient in pkg/config/v1/validation/proxy.go when transport.tcpMux/multiplexer is set to a value the server does not support.

Common situations: An unsupported or misspelled multiplexer name (supported: httpconnect) is configured for a TCP proxy. Fix by setting the multiplexer to a supported value or removing it.

AI-assisted analysis of fatedier/frp@6c8a8d0a97 (2026-08-15). Data as JSON: /api/errors/1d7aa4679d8c60fa. Report an issue: GitHub.