NWConnection with .UDP never gets beyond 'Preparing' state

Code Block 
	var connection: NWConnection?
	var hostUDP: NWEndpoint.Host = "239.255.250.78"
	var portUDP: NWEndpoint.Port = 4002
	
	func start() {
		print("UDP Provider has started")
		self.connectToUDP(hostUDP, portUDP)
	}
func connectToUDP(_ hostUDP: NWEndpoint.Host, _ portUDP: NWEndpoint.Port) {
    let messageToUDP = "ANNOUNCE"
    connection = NWConnection(host: hostUDP, port: portUDP, using: .udp)
    connection?.stateUpdateHandler = { (newState) in
      switch (newState) {
        case .ready:
          print("State: Ready\n")
          self.sendUDP(messageToUDP)
          self.receiveUDP()
        case .setup:
          print("State: Setup\n")
        case .cancelled:
          print("State: Cancelled\n")
        case .preparing:
          print("State: Preparing\n")
        default:
          print("ERROR! State not defined!\n")
      }
    }
    connection?.start(queue: .global())
  }
	
  func sendUDP(_ content: String) {
    let contentToSendUDP = content.data(using: String.Encoding.utf8)
    connection?.send(content: contentToSendUDP, completion: NWConnection.SendCompletion.contentProcessed(({ (NWError) in
      if (NWError == nil) {
        print("Data was sent to UDP")
      } else {
        print("ERROR! Error when data (Type: Data) sending. NWError: \n \(NWError!)")
      }
    })))
  }
  func receiveUDP() {
    connection?.receiveMessage { (data, context, isComplete, error) in
      if (isComplete) {
        print("Receive is complete")
        if (data != nil) {
          let backToString = String(decoding: data!, as: UTF8.self)
          print("Received message: \(backToString)")
        } else {
          print("Data == nil")
        }
      }
    }
  }