We have identified an issue with iOS11 causing the connection of cameras to be randomly very slow.
The problem is on Apple side and unfortunately, there is nothing we can do to fix it. A bug report has been submitted to Apple and it should be fixed with an upcoming update of iOS 11 very soon.
In the meantime please be patient, the camera always manages to connect to the app after 30 / 40 seconds.
Sorry for the inconvenience.