The latest update for Android and iOS turns on Bluetooth functionality for the new AirProbes. If your app is crashing try turning on BlueTooth.
If this doesn't work, see if you have additional bluetooth devices such as AirPods, connected. Try disconnecting them and all bluetooth devices. This should be a temporary thing, needed for registering only.
We are working on a fix to earphones, etc. Not all cause the issue.
Disconnect them, close the app, then try again.