CoreBluetooth XPC connection invalid

CBCentralManager reference should be a strong reference to the class as a member variable. It cannot work as a local reference.

Try next:

class ViewController: UIViewController {
   var ble: BLE!
   override func viewDidLoad() {
      super.viewDidLoad()

      ble = BLE()
  }
}

class BLE: NSObject, CBCentralManagerDelegate, CBPeripheralDelegate {
   private var manager: CBCentralManager!

   required override init() {
      super.init()
      manager = CBCentralManager.init(delegate: self, queue: nil)
   }

   func centralManagerDidUpdateState(_ central: CBCentralManager) {
      var consoleLog = ""

      switch central.state {
      case .poweredOff:
          consoleLog = "BLE is powered off"
      case .poweredOn:
          consoleLog = "BLE is poweredOn"
      case .resetting:
          consoleLog = "BLE is resetting"
      case .unauthorized:
          consoleLog = "BLE is unauthorized"
      case .unknown:
          consoleLog = "BLE is unknown"
      case .unsupported:
          consoleLog = "BLE is unsupported"
      default:
          consoleLog = "default"
      }
      print(consoleLog)
   }
}