@Kami_Mark, thank you for your quick reply.
In fact, I already did all you advise – I deleted the camera from Yi Home app, then tried to reset it.
The problem is I cannot reset: the camera does not react to Reset button pressing.While I keep the button pressed, the yellow LED is on, then I hear “click” - and the LED goes off. The camera is still alive, as infra-red lighting works.