How to close unity app in android?

I used Application.Quit() to close my unity app in android 8.1, the app was closed but restarted . And there was a message from the android system: xx app was stopped.
How can I close the app properly?

Hi, could you attach a logcat of the crash? Also, what version of Unity are you using?

Thx for your reply. Through logcat, I found the crash code. Thx!