The problem is the 55555 port, i have same problem . We can't change the port, we have devices in production that use this port. Any solution?

Same problem, here is our code, same problem with GCDAsyncUdpSocket library. If i use an other port it works. class ViewController: UIViewController {     var group: NWConnectionGroup!     override func viewDidLoad() {         super.viewDidLoad()         guard let multicast = try? NWMulticastGroup(for: [ .hostPort(host: "224.0.0.251", port: 55555) ])         else { fatalError("") }         group = NWConnectionGroup(with: multicast, using: .udp)         group.setReceiveHandler(maximumMessageSize: 16384, rejectOversizedMessages: true) { (message, content, isComplete) in             print("MESSAGE: \(String(describing: message.remoteEndpoint))")         }         group.stateUpdateHandler = { (newState) in             print("STATUS: \(String(describing: newState))")         }         group.start(queue: .main)     }     override func viewDidAppear(_ animated: Bool) {         super.viewDidAppear(animated)         send()     }     func send(){         let groupSendContent = Data("helloAll".utf8)         group.send(content: groupSendContent) { error in             if let err = error{                 print("Send complete with error \(err)")             }         }     } }