NWConnection on Watch - WiFi not working

Hey,

im trying to get the NWConnection on watchOS 6 working. The NWConnection is working completly fine in combination with the iPhone, but if I disconnect the iPhone (Airplane Mode, WiFi and Bluetooth Off) the connection is not working, but the apple watch is connected with the wifi.

Normally the Apple Watch (mine a Series 4) can connect to a server without an iPhone, too?

Here the minimal example code (Created Watch-App iOS-Project with XCode 11.5 - InterfaceBuilder). The only thing I changed is I added an Label to the Watch-Interface and the following InterfaceController.swift in WatchKit Extension:

(Just for Info. The Server will just return "OK MPD 0.19.0\n" at connect)

import WatchKit
import Foundation
import Network

class InterfaceController: WKInterfaceController {
   
    @IBOutlet weak var label: WKInterfaceLabel!
   
    private var connection : NWConnection?
    private var dispatchQueue = DispatchQueue(label: "connection")
   
    override func awake(withContext context: Any?) {
        super.awake(withContext: context)
       
    }
   
    override func willActivate() {
        // This method is called when watch view controller is about to be visible to user
        super.willActivate()
        self.label.setText("Version")
       
        let endpoint = NWEndpoint.hostPort(host: .name("192.168.178.10", nil), port: 6600)
        let parameters = NWParameters.tcp
       
        self.connection = NWConnection(to: endpoint, using: parameters)
        self.connection?.stateUpdateHandler = .some({ (state) in
            print("Received State=\(state)")
            switch state {
            case .ready:
                self.label.setText("READY")
               
                self.connection?.receive(minimumIncompleteLength: 1, maximumLength: 1024, completion: { (data, contentContext, isComplete, error) in
                    if let data = data, data.count > 0, let string = String(data: data, encoding: .utf8) {
                        let arr = string.components(separatedBy: "\n")
                        let VERSION_PREFIX = "OK MPD"
                        for item in arr {
                            if item.hasPrefix(VERSION_PREFIX) {
                                // Received Version
                                let version = item[item.index(item.startIndex, offsetBy: VERSION_PREFIX.count)...]
                                var text = String(version)
                                if let path = self.connection?.currentPath {
                                    text += " - Uses Others=\(path.usesInterfaceType(.other)) Uses Wifi=\(path.usesInterfaceType(.wifi))"
                                }
                                self.label.setText(text)
                                break
                            }
                        }
                    }
                })
                break
               
            case .waiting(let error):
                self.label.setText("Waiting Error=\(error)")
                break
               
            case .failed(let error):
                self.label.setText("Failed Error=\(error)")
               
            default:
                break
            }
        })
        self.connection?.start(queue: self.dispatchQueue)
    }
   
    override func didDeactivate() {
        // This method is called when watch view controller is no longer visible
        self.connection?.cancel()
        super.didDeactivate()
    }
}

It is because the Watch could not connect to a server without the iPhone or am I missing something?

Thanks and Regards

Adrian