Hello, I have exactly the same problem! It happens on iPhone 11 Pro iOS 13.5.1, but iPhone 11 with same iOS not. I have screen and on present ConnectionListener is initialized and on dismiss it deinitialized. First time open screen everything is ok: Listener stateUpdateHandler: waiting(POSIXErrorCode: Network is down) Listener stateUpdateHandler: ready "📞 New connection: 10.0.1.2:50655 establish" "Connection stateUpdateHandler: preparing" "Connection stateUpdateHandler: ready" but for next n-tries only this messages: [] nw_path_evaluator_evaluate NECP_CLIENT_ACTION_ADD error [48: Address already in use] [] nw_path_create_evaluator_for_listener nw_path_evaluator_evaluate failed [] nw_listener_start_locked [L3] nw_path_create_evaluator_for_listener failed Listener stateUpdateHandler: waiting(POSIXErrorCode: Network is down) Listener stateUpdateHandler: failed(POSIXErrorCode: Address already in use) Here is my code for listening inbound connection: final class ConnectionListener {            var dataReceivedHandler: ((Data) -> Void)?       private let port: UInt16   private let maxLength: Int       private var listener: NWListener!   private var connection: NWConnection!       init(port: UInt16, maxLength: Int) {     self.port = port     self.maxLength = maxLength   }       deinit {     print("❌ Deinitialize \(self)")   }       // MARK: Public API       func startListening() {     let parameters = NWParameters.tcp     parameters.allowLocalEndpointReuse = true     self.listener = try! NWListener(using: parameters, on: NWEndpoint.Port(integerLiteral: port))     self.listener.stateUpdateHandler = { state in print("Listener stateUpdateHandler: \(state)") }     self.listener.newConnectionHandler = { [weak self] in self?.establishNewConnection($0) }     self.listener.start(queue: .main)   }       func stopListening() {     listener.cancel()     connection?.cancel()   }       // MARK: Private API       private func establishNewConnection(_ newConnection: NWConnection) {     connection = newConnection     debugPrint("📞 New connection: \(String(describing: connection.endpoint)) establish")     connection.stateUpdateHandler = { [weak self] state in       guard let self = self else { return }       debugPrint("Connection stateUpdateHandler: \(state)")       switch state {       case .ready:         debugPrint("Connection: start receiving ✅")         self.receive(on: self.connection)       default: break       }     }     self.connection.start(queue: .main)   }       private func receive(on connection: NWConnection) {     connection.receive(minimumIncompleteLength: 1, maximumLength: maxLength, completion: { [weak self] content, context, isCompleted, error in       guard let self = self else { return }       if let frame = content {         self.dataReceivedHandler?(frame)       }       self.receive(on: connection)     })   }     } Maybe I have some problem in my Listener? Thanks!

I also create GitHub sample project, which is shown a problem GitHub project - https://github.com/ChoadPet/NWListenerTest/tree/master