title: VOIP token won't get invalid after uninstalling an app from a device or disconnected from the network in iOS
body: <p>I am working on one VOIP-based application where one user calls another user everything works fine like calling and all.</p>
  <p>But whenever I didn't log out from the application and directly uninstall the application at that time any another user tries to call the user who already uninstalled the application. At that time backend get a successful response from apple (i.e. 200 Success). Why won't give an error if that app is not installed</p>
  <p>Actually, we need to give some specific alert to the user who called the person who already uninstalled the application but we are unable to find from backend too that the voip push failed.</p>
  <p>One another thing just for testing : We tried to send FCM silent notification too which works synchronously with VOIP notification but in that too FCM gives success in backend while app already uninstalled from device.</p>
  <p>If anyone facing same issue and having solution regarding that then please let me know.</p>