Problem resuming audio recording

My app record audio in background mode. Sometimes the app crashes (I still don't know why) but then it restarts by the system itself. Before being closed, I pause audio recording (inside applicationWillTerminate) and I use play function, after the app reopened, inside a sync function that runs in my app every minute.


On my test mobile (Iphone 5s, IOS 13.2.3), the app never crashes (to simulate I have to close the app manually) and always works resume the audio recording in the way that I have described. In the users' mobile (several Iphone models, but higher than 5c) I see in the log file that the app could not resume audio recording after the app has crashed.


Sorry because I don't know much more information for now, but if someone could help understand why it is happening, I would be very grateful.


Thanks