Apple Airplay can only support the same Wi-Fi network, and if you cannot see the device name, (Cast-XXXX), you are on a separate Wi-Fi subnet network.
Yes, please use vCastSender iOS and key-in the on-screen connecting PIN code. Then, on the iOS device, open the Control Center and touch AirPlay Mirroring. You should see a device prefixed with “Cast-XXXX”, select it. Enter the “AirPlay Password” to mirror your iOS device to your ViewBoard.