tcpmux with multiplexer httpconnect not supported because th

Error message

tcpmux with multiplexer httpconnect not supported because this feature is not enabled in server

What it means

Error "tcpmux with multiplexer httpconnect not supported because this feature is not enabled in server" thrown in fatedier/frp.

Source

Thrown at pkg/config/v1/validation/proxy.go:209

	case *v1.SUDPProxyConfig:
		return validateSUDPProxyConfigForServer(v, s)
	default:
		return errors.New("unknown proxy config type")
	}
}

func validateTCPProxyConfigForServer(c *v1.TCPProxyConfig, s *v1.ServerConfig) error {
	return nil
}

func validateUDPProxyConfigForServer(c *v1.UDPProxyConfig, s *v1.ServerConfig) error {
	return nil
}

func validateTCPMuxProxyConfigForServer(c *v1.TCPMuxProxyConfig, s *v1.ServerConfig) error {
	if c.Multiplexer == string(v1.TCPMultiplexerHTTPConnect) &&
		s.TCPMuxHTTPConnectPort == 0 {
		return fmt.Errorf("tcpmux with multiplexer httpconnect not supported because this feature is not enabled in server")
	}

	return validateDomainConfigForServer(&c.DomainConfig, s)
}

func validateHTTPProxyConfigForServer(c *v1.HTTPProxyConfig, s *v1.ServerConfig) error {
	if s.VhostHTTPPort == 0 {
		return fmt.Errorf("type [http] not supported when vhost http port is not set")
	}

	return validateDomainConfigForServer(&c.DomainConfig, s)
}

func validateHTTPSProxyConfigForServer(c *v1.HTTPSProxyConfig, s *v1.ServerConfig) error {
	if s.VhostHTTPSPort == 0 {
		return fmt.Errorf("type [https] not supported when vhost https port is not set")
	}

View on GitHub (pinned to 6c8a8d0a97)

Solutions

Set tcpMuxHTTPConnectPort in the frps configuration so the server enables the httpconnect multiplexer.
Change the proxy to not use multiplexer httpconnect, or ask the server administrator to enable the feature.

When it happens

Trigger: Raised by validateTCPMuxProxyConfigForClient in pkg/config/v1/validation/proxy.go when a tcpmux proxy uses multiplexer httpconnect but the server has not enabled the corresponding feature.

Common situations: tcpmux with httpconnect is configured while the server's vhost http/https ports or the feature gate are not enabled. Fix by enabling the feature on the server or using a different proxy type.

AI-assisted analysis of fatedier/frp@6c8a8d0a97 (2026-08-15). Data as JSON: /api/errors/455b6618b9c0cea7. Report an issue: GitHub.